Page 1

Group Four Food Dehydrator

Dane Rickwood Samantha Kopinja Edgar Vogel Natassja Alexander i


Table of Contents 1. Design Brief .................................................................................................................................................................................................................................. 1 1.1 Summary ................................................................................................................................................................................................................................ 1 1.2 Limitations and Constraints ................................................................................................................................................................................................... 1 1.3 Requirements ......................................................................................................................................................................................................................... 1 2. Design Specifications ................................................................................................................................................................................................................... 1 3. Time Management ....................................................................................................................................................................................................................... 1 4. Research ....................................................................................................................................................................................................................................... 2 4.1 Consumer Market & Ergonomics ........................................................................................................................................................................................... 2 4.2 Standards Summary ............................................................................................................................................................................................................... 5 4.3 Research Summary ................................................................................................................................................................................................................ 6 5. Design Concepts ........................................................................................................................................................................................................................... 7 6. Design Concept Development ..................................................................................................................................................................................................... 8 7. Testing and Design Review .......................................................................................................................................................................................................... 9 7.1 Testing the Design Concept ................................................................................................................................................................................................... 9 7.2 The Final Design & Drawings................................................................................................................................................................................................ 13 Front, Rear and Isometric ...................................................................................................................................................................................................... 14 Top, Side and Section ............................................................................................................................................................................................................. 15 Outer Shell Cutting Drawing .................................................................................................................................................................................................. 16 Inner Shell Cutting Drawing ................................................................................................................................................................................................... 17 i


Component Drawings ............................................................................................................................................................................................................ 18 Front Door and Tray Drawings Tray Design Drawings ........................................................................................................................................................... 19 Tray Design Drawings ............................................................................................................................................................................................................. 20 8. Production Process and Material Selection ............................................................................................................................................................................... 21 8.1 Materials selected ................................................................................................................................................................................................................ 21 8.2 Production processes ........................................................................................................................................................................................................... 22 9. Evaluation .................................................................................................................................................................................................................................. 26 9.1 Design Specification Evaluation ........................................................................................................................................................................................... 26 9.2 Design Process Evaluation ................................................................................................................................................................................................... 28 10. Reference List........................................................................................................................................................................................................................... 30 Appendix A: Instruction Manual .................................................................................................................................................................................................... 31 Appendix B: Weekly Meeting Logs ................................................................................................................................................................................................ 36


1. Design Brief 1.1 Summary This portfolio documents the design process of an assessment item for a university industrial design course. This project is a design and manufacturing process which is aimed at producing a functioning food dehydrator. In a group, the dehydrator will be manufactured as a product that is suitable for commercial sale to Australian households.

1.2 Limitations and Constraints The project and final design outcome will be limited by several factors and constraints:       

Power supply: the unit may only be a 12 DC system Size: the unit will need to manufactured to appropriate sizes for use Capacity: how much room is needed for fruit dehydration Budget: amount agreed upon to fund the project Time: the set timeframe before the project is due Materials: the materials accessible and their ability to be manufactured in the given time frame Ability: the extent of our ability and skills places a constraint on what can be built in the given timeframe

1.3 Requirements    

The food dehydrator is required to be safe and functional. To satisfy a consumer the product needs to light and easy to use. The product should not require unpractical lengths of time to function to its full capacity. (8-10 hours dehydrating time for Fruit and vegetables) The food dehydrator is to be documented and built by 11:55pm on the 15th of April 2011

1


2. Design Specifications 2.1 Appearance a) The product should have a clean finish b) The product should be appealing to a range of consumers c) The products aesthetic characteristics should be of a competitive standard

2.2 Competition a) Product to have a competitive price as per market including equivalent products:  Excalibur  Sunbeam  Lequip  Sendona

2.5 Ergonomics a) b) c) d)

The controls of the product need to be accessible and labelled clearly Components detachable for cleaning Unit size is practical for household uses Product can be operated by one person without any difficulty

2.6 Environments a) b) c) d)

Product can be operated in all Australian climates Product will experience moist and humid conditions Noise generated by use will be minimal The product will be easy to clean, manufactured with robust materials for impacts that may occur in kitchen environment

2.7 Disposal

2.3 Customer

a) The unit will need to be disposed of in an appropriate manner i.e. taken to waste facilities service and sorted with other electrical appliances

a) Product to suit standard household kitchen b) The target should be aimed at mainstream market c) Product aimed to be used at 14+ year old consumers

2.8 Safety

2.4 Documentation a) An owner’s manual must be produced covering operation and maintenance b) The manual should also cover safety and recipes

a) Product design will inhibit dangerous levels of heat b) Heat and air movement sources completely concealed c) Product to be off when minor cleaning maintenance being undertaken d) Access to heat source (globes) for changing is safe e) No sharp edges available for contact when product is under general use

1


2.9 Maintenance

a) The product is to have an end user cost of AU $120.00 b) Manufacturing costs are to be less than or equal to (ď‚Ł) AU $100.00 c) Packaging less than 5% of manufacturing costs

a) Cleaning required after use b) Heat source (bulbs) accessible for changing c) Electrical maintenance free for the duration of the products prescribed lifetime

2.14 Dimensions

2.10 Materials

2.15 Product life

a) b) c) d) e)

a) Product to be on the market for 5 years as per the trends, competition and function b) Product parts are therefore to be available for 5 years

Manufacturing materials to be food safe Product materials are to be aesthetically pleasing Product materials are to last a minimum of 5 years Materials are to allow for temperature control Materials need to be easy to maintain (cleaning)

a) The size of the prototype will not exceed comfortable dimensions for carrying, general use and storage

2.16 Quality

2.11 Packaging

See performance

a) Packaging must not escalate costs above 5% of manufacturing costs b) Packaging to be clear, specific and recyclable c) Packaging to contain manufacturers details

2.17 Quantity

2.12 Performance a) The product must be able to dehydrate fruit and vegetables in under a maximum of 10 (ten) hours b) The product must be able to reach and maintain a constant temperature range of 54-60ď‚°C

2.13 Product cost

a) Product to be a one-off prototype

2.18 Standards a) Product will meet standards AS/NZS 3350.1:2002- Safety of household and similar electrical appliances 2.19 Testing a) Product will be tested and cleaned before submission

2


3. Time Management The following Gantt chart presents the timeline aim of our project

Table 3.1 Gantt chart showing the target timeline for the development and manufacture of the Food Dehydrator

1


4. Research To allow for a successful design and manufacturing process of a food dehydrator thorough research needs to be conducted. This section of the portfolio presents the research conducted in the areas of the consumer market, ergonomics and materials. The collaboration of this research allows for progression into section five of the portfolio which reports on formulation of design concepts.

4.1 Consumer Market & Ergonomics In order to design a product with competitive attributes a sound understanding of the existing consumer market is required. There are several food dehydrating products on the market ranging in size, colour and capability. As outlined in section 2.3 and 2.12, the aim is to design and manufacture a product suitable for everyday household use and to dehydrate fruit and vegetables. This product will be used in an average household. It is this reason that Ergonomics play a large factor in the design process. Figure 4.1 illustrates the dimensions of other typical kitchen appliances. From this figure it can be concluded that there is an average size that is satisfactory in that it is easy to lift, store and clean. Looking at the sample of appliances in Figure 4.1 shows that plastic is a common material used in the manufacturing of kitchen appliances. It is common in these kitchen appliances to have curved or blended corners and surfaces. This allows for easy cleaning and handling.

Table 4.1 on page four, compares several dehydrator models. It includes models that can dehydrate a range of foods and products with a capacity limited to one type of food i.e. fixed temperature. In comparing these leading products an idea on a standard size, capacity and aesthetics of a dehydrator can be gathered which, when drawn upon for inspiration, will allow for a competitive product in the consumer market. Figure 4.1 Dimensions and finishes of appliances found in a kitchen

2


It can be understood from the comparison table that food dehydrators are usually designed to create air flow vertically or horizontally, which is shown in figure 4.2. Written and video reviews address issues in the vertical air flow models. Vertical airflow doesn’t allow for equal heating of all trays. The bottom tray in a vertical stack receives the air flow first resulting in quicker dehydrating times at the bottom than the top. This works in the same adverse way if the fan is at the top forcing air down. For an experienced user this may be desired as they may wish to have the food item on the bottom tray dehydrated more so than the top tray. Due to the specification of this design and the intended market – novice food dehydrators – this design would incorporate the inconvenience of rotating racks and therefore is an undesired attribute of a vertical design (Food Dehydrator, 2010). A strong attribute of horizontal design is that when the air flow is equally distributed across all trays very little flavour mixing can occur. In a vertical model air has to flow through each tray on its way to the top. This results in the flavour of successive trays merging with the previous tray (Australia Excalibur, n.d).

Figure 4.2 Air flow diagram of both horizontal and vertical dehydrator models (Adapted diagram: [Australia Excalibur, n.d], [Alibaba, 2010])

3


Food Dehydrator Comparison Table Product

Lequip 524

Sunbeam DT5600

Excalibur 2500

Excalibur r3500

Ezidri classic

Lequip filter pro

Excalibur 2900

Excalibur r3900

Sedona

Dimensions HxWxD Weight Air flow Adjustable thermostat Computer controlled Temp. Built in timer On/off switch Usable size of trays Space between trays Number of trays Reusable non stick sheets Colours Warranty

203 x 431 x 279mm 3.6kg Vertical Yes

215 x 431 x 482mm 7.7kg Horizontal Yes

340mm Diameter

Vertical No

215 x 431 x 482mm 7.7kg Horizontal Yes

Vertical No

298.5 x 431 x 279mm 5.4kg Vertical Yes

317.5 x 431 x 482mm 10.0kg Horizontal Yes

317.5 x 431 x 482mm 10.0kg Horizontal Yes

371 x 431 x 500mm 10.6kg Horizontal yes

Yes

No

No

No

No

Yes

No

No

Yes

No

No

No

No

No

Yes

No

No

Yes

Yes

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

356mm x 356mm 19.05mm

356mm x 356mm 19.05mm

0.4m^2 (Total Area) 25.4mm

431mm x 279mm 25.4mm

356mm x 356mm 19.05mm

356mm x 356mm 19.05mm

356mm x 292mm 25.4mm

431mm x 279mm 25.4mm

4

5

5

5

4 (up to 10)

6

9

9

9

Yes

No

Yes

Yes

No

Yes

Yes

Yes

Yes

Grey 10 years

White 2 years

Black/white 5 years

Black/white 10 years

White 1 year

Grey 10 years

Black/white 5 years

Black/white 10 years

Black 5 years

Table 4.1 This Dehydrator Products comparison chart compares some of the leading brands and products available on the market (Adapted from: [Discount Juicers (n.d).], [Vitality for Life Australia (2007).], [LB Healing Products (2010).]).

4


4.2 Standards Summary In order to design and manufacture a Prototype food dehydrator the standards need to be identified and summarised. The follow summary is obtained from the AS/NZS 3350.1:2002 standards and includes the relevant requirements associated with this particular design and manufacturing process. AS/NZS 3350.1:2002- Safety of household and similar electrical appliances Heating 11.1 Appliances and their surroundings shall not attain excessive temperatures in normal use. Stability & Mechanical hazards 20.1 Appliances, other than fixed appliances and hand-held appliances, intended to be used on a surface such as the floor or a table shall have adequate stability. 22.5 Appliances intended to be connected to the supply by means of a plug shall be constructed so that in normal use there is no risk of electric shock from charged capacitors when touching the pins of the plug. 22.9 Appliances shall be constructed so that parts such as insulation, internal wiring, windings, commutators and slip rings are not exposed to oil, grease or similar substances. 22.12 Handles, knobs, grips, levers and similar parts shall be fixed in a reliable manner so that they will not work loose in normal use if loosening could result in a hazard. 22.13 Handles shall be constructed so that, when gripped as in normal use, contact between the operator's hand and parts having a temperature rise exceeding the value specified for handles which are held for short periods only in normal use, is unlikely. 22.14 Appliances shall have no ragged or sharp edges, other than those necessary for the function of the appliance or accessory, that could create a hazard for the user in normal use or during user maintenance. Mechanical strength 30.1 External parts of non-metallic material, parts of insulating material supporting live parts including connections and parts of thermoplastic material providing supplementary insulation or reinforced insulation, the deterioration of which might cause the appliance to fail to comply with this standard, shall be sufficiently resistant to heat. (Australian/ New Zealand Standard 3350.1:2002)

5


4.3 Research Summary Summarising the conducted research reveals that there are several factors significant and paramount to the design and manufacture of a food dehydrator. There is also supported reason for several design decisions that can be made about the design and manufacture. The following is a summary conclusive of the research in section 4.1 and 4.2:         

Plastic is a common material used in the manufacturing of kitchen appliances Metal is a common material used in the manufacturing of kitchen appliances It is common in these kitchen appliances to have curved or blended corners and surfaces Food dehydrators are usually designed to create air flow vertically or horizontally Vertical airflow can inhibit equal heating of all trays Horizontal design allows for air flow to equally distributed across all trays Dehydrators on the market range from 203 x 431 x 279mm to 371 x 431 x 500mm Dehydrators on the market range from 3.6 kg to 10.6 kg According to the standards the product needs to be safe in all factors of its design from its form to its electrical components. This includes its stability, heating, storage, use and cleaning.

Summarising the research conducted into the design of the Food dehydrator allows for an understanding of further constraints and guides that influence design and manufacturing decisions.

6


5. Design Concepts As a result of the research findings design concepts were able to be drawn. Several factors of the research were paramount in developing design concepts. Original study sketches incorporated cylindrical shaped designs with vertical airflow along with horizontal box shaped designs with curved fronts (See Figures 5.1 and 5.3). Majority of the concepts then began to heavily rely on a box shape with horizontal airflow which was an influence of the research and a solution to the design problem. Early concepts began to explore the ideas of a detachable unit for cleaning and storage (see Figures 6.1, 6.2 and 6.3) along with the possibilities of using a combination of plastic, metal and timber.

Figure 5.1 Round, vertical flow concept sketch

Figure 5.2 Early concept ideas and features

Figure 5.3 Square, horizontal airflow concept 7


6. Design Concept Development The design concept has developed further as different materials and ideas have been combined. The idea of a completely detachable unit for washing and storage has become one of the repeating design details in all the developments. Figure 6.1 illustrates the basic idea of an interlocking component system which is made completely of plastic. The progression of this idea led to the finer detailing of how the prototype will assemble and the vents/electrical components locations (as illustrated in figures 6.2 and 6.3).This idea had limitations placed on it by the manufacturing techniques i.e. the Thermo former. After querying workshop and expert personnel, suggestions were made and considered into the idea of joining plastic and how this could resolve the size and height restrictions imposed by the forming conditions of the plastic and machine. Another material, Aluminium panel, was then suggested and considered. This products capability and workability allowed for the elimination of restrictions placed on the design if manufactured out of plastic.

Figure 6.1 Beginning sketches of the detachable components

Figure 6.2 Further developments of details

Figure 6.3 Conclusive ideas sketch of design concept 8


7. Testing and Design Review In order to progress any further in the design process testing needed to be carried out. This would allow for the collection of data documenting the operation of the dehydrator and its performance in a rough but sufficient model of the general design concept.

7.1 Testing the Design Concept Four tests have been conducted in order to achieve the desired heat and air flow needed for fruit and vegetable dehydration. The following four tables present the testing variables, modifications, results and any other necessary information about that particular test. Testing was conducted via a 1:1 scale cardboard model of the general design concept of the food dehydrator. In each test all effort was made to make sure the box was completely sealed to allow each test to be as accurate as possible and for each to be conducted under the same conditions.

TEST ONE

Fan

Light

Equipment

Airflow

Temperature

Evaluation

1 x fan and 1 x globe (Globe centre back with fan blowing directly onto it) Opened at back bottom, with air coming out the front two sides of door Start 25.9C 5 Minutes 27.1C 10 Minutes 29.0C 15 minutes 31.2C Not enough heat generated, cold air from fan blowing too fast and hard onto globe

Table 7.1 Test one results, configured with a fan blowing past a light heat source onto the food trays 9


TEST TWO Fan Light Vent Hole Equipment

Modification

Airflow

Temperature

Evaluation

1 x fan and 1 x globe Shortened prototype blocked all airflows and created a chamber between electrical equipment and dehydrating area. One air vent at back centre and one at front centre. Fan in front of globe sucking hot air through to chamber One vent in the rear and one vent at the front of the model Start 28.5C 5 Minutes 30.0C 10 Minutes 32.3C 15 minutes 34.9C Still not heating up fast enough

Table 7.2 Test two results, configured with the fan drawing warm air form the heat light source at the rear

10


TEST THREE Fan Light Vent Hole Equipment

Modification

Airflow

Temperature

Evaluation

1 x fan and 2 x globe Added second globe, one globe at each side of back electrical area, fan in centre still sucking through hot air, blocked off original air holes and created 6 small holes on sides of electrical area next to the globes and created 3 holes at front section. 6 vent holes on one side of heat chamber at the rear and 3 vent holes at the front of the prototype Start 28.5C 10 Minutes 39.9C 20 Minutes 41.1C 30 Minutes 43.9C Heat is progressing faster and reaching a more accurate level for food dehydrating

Table 7.3 Test three results, configured with two lights as heat sources at the rear and air vents on one side of electrical cavity

11


TEST FOUR

Fan Light Vent Hole Equipment Modification

Airflow

Temperature

Evaluation

1 x fan and 2 x globe Decreased the existing 6 vent holes on the one side of back to two each side and only one air hole at front 2 vent holes on each side of heat chamber at the rear and 1 vent hole at the front of the prototype Start 28.5C 10 Minutes 39.1C 20 Minutes 43.4C 30 Minutes 48.1C 40 Minutes 50.0C 50 Minutes 52.1C 60 Minutes 54.3C Heat is now reaching correct temperature due to modifications

Table 7.4 Test four Results, configured as per test three with less air vents which are spread even on both sides

12


7.2 The Final Design & Drawings After the result of testing the dehydrator other design decisions in terms of the shape, size and manufacturing materials were made: 

 

The unit would no longer be detachable. It was decided that as a result of the testing a detachable unit would involve very complex joining issues in order to keep the product sealed. Although possible to seal, the detachability design concept was not a large priority as a manufacturing process as cleaning is not going to be as complicated as was factored into the original design. The unit would be constructed of Aluminium panel as it was available as a recycled material at no cost. This would be manufactured in the form of CNC Router cut and engraved net. This would then be folded and joined by glues and pop rivets. The unit would not have a larger heat compartment than that of the concept and tested design as this was unpractical in creating sufficient heat. Rather the unit will be all one unit with an internal partition for the heat compartment which would double as the frame to hold the fan.

The following pages are the drawings associated with the design of the prototype. This includes the presentation drawings, engineering drawings and DXF file drawings for the CNC router and laser systems.

13


278

Front, Rear and Isometric

208

Front door hinge

Front view scale 1:5

278

208

Screws to hold the back

Air gaps Power cable

Isometry

Back view scale 1:5

14


Top, Side and Section 360 Air gap

Front door handle

Front door hinge

Air gap

Front door hinge

208

Front door handle Magnets to hold the door

10

360

Switch

Side view scale 1:5 4

353

278 3

Pot rivets to hold the inner and outer shell

91 57

53

253

Switch

Fan

100

Slides

Slides holder

Transistor

Switch

48

7

53

3

152

Light / heat source

54

3

Rubber

Section drawing

Top view

scale 1:5

scale 1:5

15


75

23

Outer Shell Cutting Drawing

120

56

21

All foldings 3 + 3 mm

120

353

3,2 mm dia

42

42

83

42

42

154

42

50

33

17 31

42

33

75

77

42

21 3 3

56

20

23 3 3

590

NOTE: All edges folded up

119 139

3 3 21 21

73

21 167 208

73 21 21

237 278

21 21

167

21 21

208

119 139

973

Outer shell pattern scale 1:5

16


Inner Shell Cutting Drawing

120

120

55

42

3,2 mm dia

120

120

350

3,2 mm dia

68

38

38

60

42

50

42

67,5

38

38

95

10

67,5

154

40

10

38

80

77

50

30

48

42

55

3,2 mm dia

60

All foldings 3 + 3 mm

7 13

3 3

20

370

20

300

NOTE: All edges folded down

48

95

3 3 20 20

115

67,5

120 160

20 20

95

190 230

67,5

20 20

120 160

20 20

95 115

780

Inner shell pattern

connection pattern

scale 1:5

scale 1:5 17


Component Drawings

NOTE: All edges folded up

40

25

44

47

47

3,2 mm dia

119 40

115

119

15

127

15

40

79 R 38

16

R 27

3 3

7,5 mm dia

230

40

10

40

28

80

40

40

3,2 mm dia

8 11

6 mm dia

All foldings 3 + 3 mm

20

16

80

115

167

160

80

R 37 40

71

20 67

40

20

40

160

All foldings 3 + 3 mm

21 32 21

40

4 R6

3,2 mm dia

20

5 R7

R 64

All foldings 3 + 3 mm

40

71

NOTE: All edges folded up

95 95

150

237

67

40

40

230

Fan holder pattern

Backdoor pattern

Light holder pattern

scale 1:5

scale 1:5

scale 1:5 18


Front Door and Tray Drawings 227

227

4 15 16 16

64

44

69

15

85

230

11

230

15

4mm dia

203

2 18 18 6

4 16 16 7

6

69

44

273

2 14 18 18

Front door pattern

Lower tray pattern

Upper tray pattern

scale 1:5

scale 1:5

scale 1:5 19


Tray Design Drawings

Tray Designs scale 1:5

20


8. Production Process and Material Selection 8.1 Materials selected Materials used to build the dehydrator need in depth consideration as they have to be able to insulate, be cleanable and food safe. As outlined in section 2.10 Materials, it is specified that the material will last five years and be able to handle the heating required for the product to operate and function and produce the desired outcome. The follow materials were selected for the project: Aluminium Panel Aluminium panel (two thin sheets of aluminium cladding a poly internal layer) is easy to engrave and cut on CNC operated machinery, creating nets which then can be folded into shape and fixed into place. The insulation properties of the aluminium panel would create a successful heat chamber in the rear of the design and allow for heat maintenance in the front with minimal heat loss. Providing a coated aluminium surface, aluminium panel allows for easy cleaning and ideal aesthetics for the outer and inner shells of the design prototype. Because of the workability of aluminium panel it also proved a suitable material to manufacture the internal partition/ fan brace along with the brace to support the lights. Acrylic (Perspex) Acrylic is a suitable material for the front door and drying trays as it is clear and can be cut on the CNC laser system to exact shape. This creates accuracy in the location of cuts, rastering (engraving) and location of holes. The door of the unit should ideally be clear as it allows the fruit and vegetable being dehydrator to be monitored without opening the unit and allowing the temperature to drop significantly. The trays could easily be cut into suitable mesh shapes on the laser system to allow air flow through the entire unit improve the dehydrating quality of the design. Acrylic is food safe. The product also incorporated other materials in various forms for construction:  Pop rivets for joining  Metal handle and hinges for the door  Rubber feet and tray supports  Magnets for the door latch

21


8.2 Production processes In this section the process of manufacturing the prototype are outlined along with any design changes that occurred during manufacture. After all the materials had been selected and obtained the final drawings were able to be constructed. Then the production process started as follows: 1. Designed the prototype in detail and prepared cutting DXF files for the CNC router to cut the Aluminium panel. 2. The aluminium panel was then cut in the CNC router using the cutting drawing files:

Figure 8.1 CNC Router cutting and engraving Alu-panel

Figure 8.2 CNC Router cutting and engraving Alu-panel

Figure 8.3 CNC Router cutting and engraving Alu-panel

3. Then the bottom and two sides of the fan holder were attached into to the inner shell. The inner shell could not be closed until the fan had been attached to the inner partition

Figure 8.4 folding the net of the inner shell

Figure 8.5 the two shells joined

Figure 8.6 the fan and light brace attached to inner shell

22


4. 5. 6. 7. 8. 9. 10.

The light brace was attached to the inner shell via the pop riveter The fan cover and fan itself were marked onto the inner shell so holes could be drilled The outer shell was folder and pop riveted together Inserted the inner shell and pop riveted it to the outer shell The fan was then attached to the inner partition Designed the trays and door to be inserted into the CNC Laser The trays and door were then cut in the CNC laser system:

Figure 8.7 laser cutting the front door

Figure 8.8 the completed laser cutting of the door

Figure 8.9 the laser cut trays

11. Then the wiring of the circuit was finished, threaded it through the rear cover and inserted into the unit. In this stage of the manufacturing process it was decided that the design would no longer incorporate a switch in the unit itself, rather and inbound switch on the power cord would be more sufficient. 12. The handle was then attached to the door using double sided tape as the holes in the drawing for the CNC laser system did not match up to the thread holes on the handle itself. This option was adopted rather than drilling holes into the acrylic because of the risk of cracking the door. 13. Then tray holders were Inserted into the unit and placed trays into the unit. Pre adhesive rubber feet were used on the bottom of the unit and as tray holders inside the unit

23


Figure 8.10 the wiring complete

Figure 8.11 tray holders being measured and inserted into design

Figure 8.12 trays being inserted into design

14. The door was then attached to the door using Butt hinges. The hinge was attached using double sided tape as the tap and die set that would be required to create a thread on the acrylic would have a cracked the door. This would have been the same outcome had pop rivets been used to attach the hinge to the acrylic door. 15. The back cover of the door was then attached. This process in the manufacturing process required another design change as our cutting drawings were slightly miscalculated. The folds in figure were designed for the rear cover attachment but the pre routed holes did not line up. Instead some metal angle was cut and tapped to allow screws to penetrate and attach the rear cover.

Figure 8.13 attaching the door to the unit

Figure 8.14 fixing the aluminium angle to the unit

Figure 8.15 attaching the back cover to the unit

24


Figure 8.16 the completed product

Figure 8.17 the completed product in operation

25


9. Evaluation The final outcome of the prototype dehydrator was a success. There were a few faults and weaknesses in the design and manufacture but the end product dehydrated fruit successfully in the desired time frame. It is safe to a significant degree and aesthetically pleasing. Various constraints placed significant pressure on design decisions and manufacturing time in which various areas required more or less attention. The follow section is an evaluation of the final product in relation to the specifications set before the design and manufacture process began and the production processes that were taken.

9.1 Design Specification Evaluation Appearance The final product was manufactured to have a clean finish and what we have considered; sound aesthetic characteristics. This would allow the product to be appealing to a range of customers. The design and manufacturing process resulted in a product that met the specification for appearance. Customer The prototypes aesthetics and ergonomics make it suitable for the average household kitchen, suited to the mainstream market. The product is easy to use and is satisfactory for 14+ year users. Ergonomics The controls for the product are not labelled as clearly a specified. This is due to a design change part way through the manufacturing of the prototype. The use of an inbound switch is easy and accessible but not clearly labelled. Time constraints in manufacturing process needed to be counted for in order to successfully meet this specification. The components of the dehydrator are not detachable. This did not meet the specification regarding this, set in this section. A decision was made in the testing process that this was not as a necessary a specification as previously accounted for and was disregarded from the design. The product is easy to operate and clean. Environments The product functions in Australian climates. Its electrical components are sealed, inhibiting any damage from moist environments. The noise generated by the unit is minimal. It is a robust prototype and easy to clean, suited to the kitchen environment. Safety The product does not reach temperatures in any part of the design that are accessible to cause burn. The heat and air flow sources are completely concealed. It is safe to access the globes for changing. The corners of the product have created sharp points. This was a result of the fold of the net to form the shell of the design. This may have been able to be alleviated through better design. As a resolution the corners have been filed down to improve this danger. 26


Materials The materials used are food safe and aesthetically pleasing. They are robust and durable, allowing the product to have a 5 year life span minimum. The manufacturing method and material combination allows for temperature control due to the prototypes insulation properties. The product is easy to wipe Performance The dehydrator was operating for 7.5 hours to dehydrate 3mm slices of apple. A constant temperature range of 52-59C was maintained during the dehydrating process. The product has successfully performed to its purpose. Product cost The total expenditure for the manufacture of the dehydrator calculated to be $84.40. This was inclusive of parts bought, $54.40(handle, Feet etc) and the $30.00 laser cutting charge for manufacturing cost. The prototype came $15.60 under budget resulting in a total profit –if sold for the competitive price of $120.00–of $35.60 for the prototype. Standards The dehydrator is generally safe to use, stable and does not provide any electrical risk. As previously mentioned there is one issue that does not conform to standards and that is the sharp corners that resulted from manufacturing methods

27


9.2 Design Process Evaluation Collaborative research was a fundamental part of our design process. Having background knowledge of existing dehydrators and making critical evaluations of their materiality and design vs. functional performance effectively informed the development of our conceptual design. It also significantly reduced errors during the prototype trial/design testing stage of the project. As well as research, constant communication between group members was the driving force behind our design. Every single idea/modification in the period prior to manufacturing was thoroughly discussed and justified to ensure that it complied with our design brief and standards. Our selection of materials and the equipment used was guided by what was available in the workshop, the knowledge of our tutor/supervisors and our design goals for the dehydrator. As a group we decided to create a long-lasting product by eliminating the use of glues and adhesives for joinery work. We managed to achieve this by using the CNC router to cut a complex net design comprising of two shells of alu-panel which were pop-riveted together. The well-thought out process of designing and constructing allowed us to create a durable, aesthetically pleasing, easy to clean framework for the dehydrator that meets a commercial/domestic standard. As the manufacture process continued there were several inconvenient setbacks. The fan was attached incorrectly and there were some errors with the laser-cut holes. Consequently, we had less time to work on the electrical compartment of the food dehydrator. One of the compromises included the use of double-sided tape and metal angles so that we could screw on the back door of the electrical compartment. Our corrections were not ideal as we did not consider how the double-sided tape would react when exposed to temperatures above 50⠰C; however, it was the most time efficient solution. Another issue neglected due to time constraints was the wires and transformers being directly exposed to the intense heat of the halogen lights. We had intended to create an insulating, protective shell to prevent the electrical from over-heating but did not manage our time properly. Instead, ventilation holes were moved from being on the sides to the back so that cooler air could be drawn in over the electrical parts. After 8 hours of operating the food dehydrator the wires and transformer continued to work under the heat of the lights. The transparent, acrylic front door of the food dehydrator also underwent a number of design changes during the manufacture process. We could not find the magnetic seal specified to seal the front door in the original design and the rubber alternative we found was not food safe. Instead we fixed the door with hinges and magnetic strips which left a void between the door and the dehydrator for ventilation. Fortunately, the outcome of this modification was more aesthetically appealing than planned and still allowed the appliance to effectively dehydrate fruit. The engraving of “Hydrowflow 3000� and the product logo also allows air to flow through. This was unintentional but did not affect the functional performance of the dehydrator.

28


A few issues with the layout of cutting drawing file for the CNC systems used also occurred. The holes laser cut in the acrylic door for the handle did not align with the thread holes in the handle itself. Rather than drill holes into the acrylic door and risk it cracking he handle was double sided taped to fix in place. Again this correction was not ideal as it did not guarantee a quality product to level of standard targeted. Time constraints and lack of material meant that we were only able to manufacture 2 drying tray instead of 3. This was due to the fact that the acrylic being used for the manufacture of the trays was scrap pieces perfect size for use. This allowed for less waste overall in the workshop environment. Overall, the design process was highly successful. As a group we all worked effectively and efficiently throughout the entire project and the food dehydrator is of quality design and function.

29


10. Reference List Alibaba. (2010). Four in one food dehydrator. Retrieved 15th March, 2011, from, http://www.alibaba.com/productgs/321275555/4_in_1_Food_Dehydrator.html Australia Excalibur (n.d). Excalibur compact dehydrator. Retrieved 5 March, 2011, from http://www.excaliburaust.com/index.php Australian/ New Zealand Standard 3350.1:2002- Safety of household and similar electrical appliances. (2002). Retrieved 8 March, 2011 from Newcastle University Library Database

Discount Juicers (n.d). Dehydrator comparison chart. Retrieved 5 March, 2011, from http://www.discountjuicers.com/dehydratorcompare.html Food Dehydrators. (2010). Types of dehydrators. Retrieved March 14, 2011, from http://blog.food-dehydrator.com/2010/10/types-ofdehydrators.html

LB Healing Products (2010). Dehydrators. Retrieved 5 March, 2011 from http://www.grainmills.com.au/category49_1.htm The Dry Store (n.d). How to dehydrate foods. Retrieved 8 March, 2011, from http://www.drystore.com/page/page/1346972.htm Vitality for Life Australia (2007). Food dehydrator comparison chart. Retrieved 5 March, 2011, from http://www.vitality4life.com.au/living-food/food-dehydrator-comparison

30


Appendix A: Instruction Manual

31


Hydroflow 3000 Instruction Manual

Page 1 of 5


CONTENTS Saftey Precautions .................................................................................................................................................................................................................... 2 Features ...................................................................................................................................................................................................................................... 3 How to use the Hydroflow 30000 ............................................................................................................................................................................................ 4 Cleaning and Maintenance ...................................................................................................................................................................................................... 4 Drying Records Chart ............................................................................................................................................................................................................... 5

SAFETY PRECAUTIONS         

Important: Read all instructions carefully before first use. To prevent electric shock and damage of drying motor never immerse the appliance in water/liquid. Always operate dehydrator on a level surface. Do not use the dehydrator in confined spaces. Do not move or cover the appliance whilst operating. Unplug the dehydrator when not in use and before cleaning. Always turn the power off at the power outlet before you insert or remove a plug. Never leave an appliance unattended while in use. Close supervision is required when the food dehydrator is being operated by children.

Page 2 of 5


FEATURES The on/off switch is built into the black electrical cord at the back of the food dehydrator. Electrical components secured in a sealed compartment at the back.

Protective cover for drying motor.

2 x Drying racks carefully designed to maximise airflow and enhance efficiency. The smooth and continuous surface of the inner shell makes cleaning easy.

Transparent cover allows you to monitor the food without interrupting the drying process.

Rubber feet hold the dehydrator in place and prevent it from scratching the bench top.

The appliance is constructed with two shells separated by an air void to insulate and prevent the external surface from overheating.

Magnets used to secure door whilst the dehydrator is operating.

Page 3 of 5


HOW TO USE THE HYDROFLOW 3000 Remove all packaging. Place the food dehydrator on a flat, heat-resistant surface, and use in a well ventilated area. Place prepared fruit onto the drying trays Turn the dehydrator on. Do not move or cover the food dehydrator whilst operating. Allow appliance to run for the time designated in the “Drying Chart for Fruit� or monitor the process to determine specific drying times. To disconnect, switch the appliance off before unplugging from the electrical outlet.

CLEANING AND MAINTENANCE 1. 2. 3. 4. 5.

Unplug the dehydrator when not in use and before cleaning. Allow unit to cool before cleaning. Clean with a damp cloth and mild detergent. Do not immerse the drying motor/ electrical components in water or liquid. Do not clean with metal scours/steel wool as it will damage the finish.

Page 4 of 5


DRYING RECORDS CHART Variations in drying times are affected by the size, thickness and the moisture content of the food. For best results keep records of humidity, weight of food and drying times. The data below is only a guide.

Food

Pre Treatment

Setting/drying time

Apples 5mm slices

None

8-10 hours

Apricot halves, destoned

None

12-14 hours

Banana Halves

Soak in lemon juice

12 hours

Grapes

Blanch

14-16 hours

Kiwifruit, peels, 5mm slices

None

6 hours

Pear, 1cm slices

Soak in lemon juice

10-12 hours

Note: Some drying times gathered from the “Sunbeam Food Dehydrator Instruction Booklet, DT5600�

Page 5 of 5


Appendix B: Weekly Meeting Logs

36


Group Number: FOUR

PROJECT MEETING LOG

Meeting Date: 07/03/2011

Time: 5:00pm

Team Members Present: Natassja Alexander Dane Rickwood Edgar Vogel Samantha Kopinja

Report on Carried Over Actions or Items

Member Reporting

N/A

N/A

Issues Discussed

Participating Member

Communication

Samantha Kopinja

Meeting Time

Natassja Alexander

Early actions to begin

Dane Rickwood Edgar Vogel

Decisions 

Communication is best done by a group e-mail where we each attach information and questions etc. and circulate between the group

The meeting times have been set to meet up to two times a week

We will begin on the Portfolio and create concepts for Wednesday morning the 9/03/2011

New Actions

Member to Action

Prepare circulation e-mail

All

Each create some concept designs

All

Begin the setting out of portfolio

Dane Rickwood

Members in Attendance Sign-off


Group Number: 4

PROJECT MEETING LOG

Meeting Date:

9/3/2011

Time: 10-12pm

Team Members Present: ALL

Report on Carried Over Actions or Items

Member Reporting Sam Kopinja

Issues Discussed

Participating Member

Design concepts

ALL

Design specifications

ALL

Materials

ALL

Available equipment and limitations

ALL

Skill capabilities

ALL

Sketches

ALL

Decisions By looking at all the sketches from the group we have drawn a final concept which we have decided to further develop. We have developed our design specifications for the portfolio. Discussed with advising teachers on equipment available and their limitations and also materials. Discussed our background knowledge and skills.

New Actions

Participating Member

Make cardboard model.

Tash

Research material availability, costs, standards etc

Sam and Eddy

Portfolio up to testing and design review

Dane

Upload all research and sketches

ALL

Members in Attendance Sign-off ALL


PROJECT MEETING LOG

Group Number: Four

Meeting Date: 16/03/2011

Time: 12:00 – 1:00

Team Members Present: All

Report on Carried Over Actions or Items

Member Reporting

Cardboard prototype was built and ready for testing

Tash & Eddy

Plastic materials for plastic forming were researched

Sam

Standards

ALL

have

not

been

located

on

small

applicances, waiting for e-mail from tutor Portfolio is up to required stage with minor

Dane

alterations needed

Issues Discussed

Participating Member

Alteration of concepts due to testing:

ALL

Temperature and Air circulation

Insulation

Size of the prototype

Number of fans and heat source globes

Possibility of requiring electrician to tag joint globe component

Diming switch

Wiring the electrical components

Decisions Concept needed to be slightly altered as it was too large/ too much air flow Prototype may need metal/reflective lining to create heat required Two globes will be used which will require tagging by electrician New Actions

Member to Action

Gantt chart updated

Sam

Testing results recorded and documented for

Sam

portfolio Photos of testing process to be uploaded

Eddy


Portfolio updated to production and material selection

Dane

Concept development sketches prepared for portfolio

Tash

Standards located and adopted

Dane

Research materials other than plastic

Eddy & Dane

Members in Attendance Sign-off


Group Number: 4

PROJECT MEETING LOG

Meeting Date:

23/3/11

Time: 12-1

Team Members Present: ALL

Member reporting Report on Carried Over Actions or Items Portfolio updated to production and material selection was not completed

Dane

Concept development sketches prepared for portfolio

Tash

was not done as concept still being developed

Dane

Research materials other than plastic- Alupanels?

Eddy & Dane

Issues Discussed

Participating Member

Testing is complete with temperature being met

ALL

Materials, equipment and manufacturing processes. Prototype modified to reach temperature

Decisions Changed Materials- alupanel and acrylic Dehydrator shape was downsized

New Actions

Member to Action

Portfolio updated (carried over actions)

Dane

Concept development sketches prepared for portfolio

Tash and Dane

and construction drawings Testing updated and getting the electrical wired

Sam

Food safety standards

Eddy

Members in Attendance Sign-off

ALL


Group Number: 4

PROJECT MEETING LOG

Meeting Date: 30/03/11

Time: 11.00am

Team Members Present: All

Report on Carried Over Actions or Items

Member Reporting

Portfolio not updated

Dane

Dimensioned drawings of revised design completed

Tash

Getting the electrical wired

Sam

Food safety standards need to be summarised

Eddy

Issues Discussed

Participating Member

Specific measurements and fixing details

All

Cad programs to be used for CNC and file formatting

Decisions

Use Archicad to prepare the net shapes for the outer and inner shells All fixings to be pop riveted (using air compressor)

New Actions

Member to Action

Draw net shapes into Archicad

Eddy

Make a new model to test accuracy cad drawings

Tash

Summarise food safety standards

Sam

Update portfolio

Dane

Buy materials: magnetic sealing strips, switch,

All

rubber feet, handle, hinges Members in Attendance Sign-off All


Group Number: Group 4

PROJECT MEETING LOG

Meeting Date:

6/4/11

Time: 12-1

Team Members Present: Sam, Eddy, Dane

Report on Carried Over Actions or Items

Member Reporting

Summarise food safety standards

Sam

Update portfolio

Dane

Buy materials: magnetic sealing strips, switch,

ALL

rubber feet, handle, hinges

Issues Discussed

Participating Member

Time management

ALL

Extra manufacture meeting times next week Manufacturing steps

Decisions Extra time required next week to complete project

New Actions

Member to Action

Engineering drawings

Eddy

Purchasing of equipment

Dane

Drawings for trays

Eddy

Summarise food safety standards

Sam

Update portfolio

Dane

Instruction manual

Tash

Members in Attendance Sign-off ALL


PROJECT MEETING LOG

Meeting Date:

Group Number: Group 4

13/04/11

Time: 12-1

Team Members Present: Sam, Eddy, Dane, Tash

Report on Carried Over Actions or Items

Member Reporting

Engineering drawings still need to be completed

Eddy

Purchasing of equipment complete

Dane

Drawings for trays complete

Eddy

Summarise food safety standards to be completed

Sam

Update portfolio in progress

Dane

Instruction manual in progress

Tash

Issues Discussed

Participating Member

Manufacturing of dehydrator

ALL

Short term time management for portfolio to be completed on time

Decisions

Had to allow for only two trays rather than three Did not use screw on front door for aesthetics rather used double sided adhesive Fixing the door and other components underwent design changes as a response to unforseen manufacturing problems

New Actions

Member to Action

initiate decisions that were made to allow for

ALL

completion on time Design drawings need to be complete

Eddy

All drawing and photo files to be uploaded

Eddy and Tash

Time management evaluation

Sam

Food standards to be summarised

Sam

Instruction manual to be completed

Tash


One more meeting for completion of manufacturing

Tash and Dane

Evaluation completed

Dane and Tash

Information be compiled for insertion into the folio

Dane

Members in Attendance Sign-off ALL

boo  

boo jjijio hhjojoij jnhjhohj

Read more
Read more
Similar to
Popular now
Just for you