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Machine converted by Lieven Standaert & Kurt Van Houte, www.repairable-‐machines.be A digital version of this tutorial can be found at www.budalab.be Tutorial written by Lieven Standaert Published as Creative Commons – Share and Share alike, 2015
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ABOUT THIS TUTORIAL 4 PREPARING YOUR FILE: WHAT YOU SHOULD KNOW 5 GETTING STARTED: HOME THE MACHINE 6 HOMING 8 PREPARE THE TOOLHEAD 8 PREPARE THE TABLE SURFACE 12 FIX YOUR MATERIAL: part 1 13 FIX YOUR MATERIAL: part 2 15 SET THE ORIGIN AND Z-‐HEIGHT 16 OPEN THE EXAMPLE FILE 18 CHECK THE SIZE 19 THE MACHINE DOES NOT DO THE THINKING FOR YOU 21 PREPARING STEP 1 22 TURN ON THE TOOL AND THE DUST EXTRACTOR 23 START STEP 1 24 START STEP 2 25 START STEP 3 27 TURN OFF VACUUM, DUST EXTRACTOR, TOOL 28 CLEANUP 28 CONGRATULATIONS, You’’ ARE DONE! 28 -‐
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ABOUT THIS TUTORIAL In the margin of this tutorial you will encounter these icons:
This signifies a task to be executed.
At this point you should ask a lab supervisor to check your work before you proceed further.
This signifies an important remark on safety.
The goal of this tutorial is not to teach you everything there is to know about milling. Rather the objective is to teach enough so you can use the machine in a safe way, without hurting yourself or the tool. To achieve this you will mill an example fil, this arrow:
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PREPARING YOUR FILE: WHAT YOU SHOULD KNOW -‐The software accepts DXF-‐files. Most software allows to save in different versions of DXF. Choose the oldest version where your file still looks ok. I use Autocad and export as DXF release 12. I convert all fonts to curves before I do this. -‐The correct units are centimeters (if you draw in millimeters, your drawing will be 10x too large, you can correct this in the software) -‐The software does not correct for the diameter of the tool, you should implement an offset in your drawing if you need accurate dimensions.
Original drawing in black. Lines in red are a 3mm offset to correct for a 6mm milling tool. -‐A mill cuts sideways. A drill cuts downwards. You cannot use a milling tool to go straight down. This means you should not try to cut a 6mm diameter hole with a 6mm tool. Instead implement a larger hole size or a smaller milling bit.
UNDERSTANDING THE LIMITATIONS OF THE MACHINE Converting a textile cutting machine to a milling machine, presents us with a couple of limitations:
1-‐The software will not offset for the milling bit diameter, as described above. 2-‐ Z-‐height is limited. This machine can mill flat boards up to 24mm thick, but cannot do 5
thicker materials.
GETTING STARTED: HOME THE MACHINE
0-‐ Make sure the machine table is free of obstacles. When we start the machine the toolhead will move to the front and to the left, with enough force to hurt you, your laptop or anything else that is in its path. 1-‐Turn on the air compressor. The machine has moving parts which use compressed air. Without sufficient air pressure, the machine will not work. You can find the red air compressor in the woodworking room.
Go find the air compressor and turn it on (red button on the control box) Next you need to locate the emergency stop and the machine controller
When you found the controller, ask for a lab supervisor to check the machine. The lab supervisor will check: -‐if the work surface is clear 6
-‐if the air compressor is turned on He/she will also assist you with the next step.
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HOMING Turn the machine on by releasing the emergency switch. You do this by rotating the button. The controller should now display “Press any button to home the machine” Press any button. The tool head should now run to the front left corner of the machine.
PREPARE THE TOOLHEAD We will be using the milling tool. 0-‐ To ease access, raise the toolhead to its maximum height using the black turnwheel on top of the toolhead. 1-‐Start by removing the cutting and creasing tools. You can detach these with an allen key.
Remove both the directional knife, shown here, and the creasing tool..
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2-‐ Find the box labelled “BUDA snijplotter” . Put the removed tools in this box so they do not get lost. Look inside this box for a 6mm milling cutter.
3-‐ You will need a hex wrench nr 15 and nr 17 to change the milling bit on the Kress tool.
4-‐Remove the tool collet from the Kress tool and have a look at it:
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These collets come in a series of sizes. They do not work like the chuck of a drill, where one size fits all, but are much more accurate. You need the one that is just a little bit larger than the milling bit shaft. Find the 6mm collet and use it with a 6mm milling bit.
5-‐ Mount the milling bit, using the two hex wrenches. It should extend MAXIMUM 30mm. For this tutorial we will be milling 8mm plywood, so we do not actually want it to stick out that far. Have the milling bit extend about 15mm. Consult the guidelines in the box below “How long …” to determine the optimal length of the milling bit in different situations. 10
You will notice at one point you will be a hand short. Either ask someone to help out, or find a block of wood to rest the bit on as shown in the next picture.
6 Verify the tool length with a tape measure. This is important as this will minimize your chance of damaging the machine.
HOW LONG SHOULD THE MILLING BIT BE STICKING OUT?
-‐It should be longer than the thickness of the material you want to cut. -‐It should be shorter that the thickness of the material plus the thickness of the spoiler board.(12mm) This reduces the chances you will mill into the nylon floor of the machine. -‐It should never be longer than 30mm, as by then it will be longer than the ‘touch’ probe that is used to measure the material.
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PREPARE THE TABLE SURFACE When cutting fabric the table surface is covered with a thick felt. When milling we will protect the table with 12mm MDF. This is called a spoiler board. As we cut through our material, we will cut a bit into the spoiler board, which will degrade over time. We will not cut into the felt or in the nylon table surface. Or at least, that is the idea * fingers crossed* Find the MDF boards and cover the table surface.
REMOVE THE FELT LAYER FIRST? If you want to cut the maximum thickness (24mm plywood board), you can gain 5 millimeters in Z-‐height by removing the felt first. For thinner boards this is not necessary.
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FIX YOUR MATERIAL: PART 1 For this tutorial we will use a piece of 8mm 600x480 poplar board. You can find these boards in the shelf behind the machine. Place the poplar board on top of the spoiler board.
If you have used this machine before as a textile cutter, you know this already: The machine comes equipped with a vacuum table. The white nylon table bed under the felt has a large number of small holes which suck the material onto the table. The vacuum works through & through the spoilerboard, as MDF is porous. 13
Let’s try this: Next to the red air compressor you turned on earlier, you can find the vacuum pump. Use the large black switch to turn it on.
G The vacuum table is divided in 3 zones. Go back to the table. At the side of the controller you should find the 3 switches you see above. Flip the back 2 up and the first one down. This selects the front third of the table. Now push against your small board. Can you feel the suction? 14
FIX YOUR MATERIAL: PART 2 This vacuum works great for large sheets. It also works better when you cover the unused parts of the table. For the small sheet we use in this tutorial we don’t trust the amount of suction, so we advise a second method of fixing your sheet: In the “BUDA snijplotter” box you can find screws in different sizes. Pick a size that is shorter than the thickness of your material +12mm (you do not want to screw into the nylon table surface, only in the spoiler board)
Fix the poplar board with a screw in each 4 corners.
Now ask a lab supervisor to check your work. He/she will check:
-‐if you are using the correct spoiler boards and material -‐if you are using a correct milling bit and it does not stick out too far -‐if you have properly removed the directional knife and the crease tool -‐if you have properly fastened the poplar board. 15
SET THE ORIGIN AND Z-HEIGHT Next you will position the tool in the bottom left corner of the board of poplar wood.
Take the controller and move the toolhead to the desired position using the arrows. 1-‐Press ‘Origin’ on the controller. Press ‘Ok’ 2-‐Press ‘7’ on the controller. This will select tool nr 7, which is the router. Next we will have the machine measure the Z-‐height of the material. 3-‐On the controller, press ‘Menu’ and then choose ‘Calibrate tool’. The machine should move, put down the probe on the left side of the toolhead onto the material and then retract a bit. It will then ask you to manually lower the toolhead onto the material. This is done by turning the large black wheel on top of the toolhead, behind the router.
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Rotate the knob until the milling bit touches the top of the material. Follow the instructions on the controller and complete this process by pressing any key.
ACCURATE Z-LEVELLING There are several tricks to get the Z-‐height dialed in with greater accuracy. One is to slide a piece of paper back and forth between the milling bit and the material while lowering the tool. When the paper gets stuck and you can no longer move it, the tool is at the correct height. For this exercise we can just eyeball it.
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OPEN THE EXAMPLE FILE The machine is all set up now. You will now open an example DXF and configure the settings to mill this example. Go to the computer connected to the machine. The software is called ‘Frontend’ You should find a shortcut named ‘Front’ on the desktop. Double click to open. De voorbeeldfile vind je in c:\Tutorial 2D milling\tutorial_arrow.dxf
Open the file and have a look at it:
You should see a similar file as the picture above, with 3 different colours. The text, the arrow and the four little holes should be on different layers/colours.
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CHECK THE SIZE In the menu ‘View’ click ‘Show Material’ and specify the size of your board.
The board size of the plywood is 600x450 mm. Click OK.
The software will now show the board as a white rectangle in relation to the drawing. In the image below you can see the white rectangle in the bottom left corner. (it is easier to see on the computer screen). My drawing is 10x too large.
Go to ‘Edit’ > ‘Scale’ in the menu and rescale the image to 0.1 The arrow should now fit 19
inside the white rectangle:
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THE MACHINE DOES NOT DO THE THINKING FOR YOU Now, if this was the lasercutter, we would just adjust the power settings for the material and go. On a milling machine you cannot do that. Everything needs to be fixed in place and stay fixed. If we would execute this file, the machine would cut out that arrow from the board. This arrow would then be loose and a soon as the tool would push against it, it would move, get flung through the lab or dig itself into the tool. It would be a mess. There are a number of tricks to deal with this. Depending on your design you might have to think up your own way to fix stuff in place. Here is how we will do it for this example:
STEP 1: -‐we will first mill het 4 holes all the way through -‐we will also mill the letters, but only 4mm deep
STEP 2: -‐we will then drill 4 screws through the holes and drill screws into the letters.
STEP 3: -‐only then we will mill the letters all the way through and mill the arrow, making sure we do not cut out the holes agein (there are screws there now) -‐we will then remove all screws and remove our finished part. Like I said, there are other ways to do this, but this is fast and gives us a finished piece without scars. The main risk is that you would hit one of the screws with the milling tool, which would be bad. This technique has the advantage thought that no clamps or mounting tools are sticking out above the milling surface. (which is good, considering the low Z-‐height of the machine) 21
PREPARING STEP 1 In the top-‐left corner of the drawing window, right click. You should see a dropdown where you can select ‘Job Ticket’
This can be tricky to find the first time. It is not the software window, but the corner of the window in which your drawing is opened.
You will see a window similar to the one in the image above. -‐It will show a bar with’ Pens used 2, 4,8’ The colours of these numbers match up with colours in your drawing. -‐You can ignore the ‘Caliper’ and ‘Cutting Mat’ settings -‐You should set 4 operations in the bottom window, to match the 4 lines in the image above:
HPGL Pen -‐ this is the layer which will be cut Operation -‐ Choose Cut, but this does not seem to matter Tool – Choose Drag Knife Pressure – Leave as is, does not matter Depth -‐ no more than 4.5 per run, so for the holes we add 2 operations, once at 4.5mm and once at 9mm (the full depth of the board) Vel – the speed with which to cut. 20 is decent, you can go slower if you want
IMPORTANT NOTE -‐The router tool is called ‘Drag Knife’. This is the tool you need to select -‐The depth is configurable, but you should not try to cut through 18mm plywood in one go. Instead you should do several runs at 4 or 5mm per run. -‐If you ignore the advice in the line above, the tool will overheat and become blunt. 22
TURN ON THE TOOL AND THE DUST EXTRACTOR The milling motor control is manual. Lift up the plexiglass dust cover door and turn on the tool. The switch uses a double motion; you should press down and then inwards.
If the milling motor starts up, close the cover. If not, check the power connection. (The 220V power cord of the milling motor exits the machine in the back, below Pieter’s desk) Next start the dust extraction system. For now this is the yellow-‐hooded little vacuum cleaner:
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Now ask for a lab supervisor to check your work. He/she will check: -‐if the size of your drawing is correct
-‐if the depth settings in the software are correct -‐if you have turned on the milling tool and dust extraction thingie
START STEP 1 When the lab supervisor has checked your work, click ‘RUN’ in the ‘Job Ticket’ popup. A second popup will show, saying ‘Save’. Choose ‘Temporary’ and click ‘Ok’
The machine should start and cut step 1.
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START STEP 2 When the machine has finished milling step 1, use the controller to move the toolhead clear. Use a cordless drill to fix all pieces in place, as described in the previous chapter. Take care not to use screws longer than 20mm (8mm poplar + 12 mm spoiler board)
This is what the fixed part should look like.
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ANOTHER FIX-STUFF-IN-PLACE TRICK You might have noticed I smuggled in another fixation trick into this example. The ‘U’ of ‘BUDA’ has 2 small tabs designed into it, which will keep it attached to the arrow. So the ‘U’ does not need screws. I’m not a great fan of this method, as it will leave you with a ‘scar’ on your finished part, but: -‐it is idiot-‐proof and you do not need to worry about the screws -‐it works ok with more brittle materials, like plexi, that do not take screws well -‐you can keep a lot of small parts together in one board for transport, Revell-‐kit style. -‐if you use this method, make sure the tab size is larger than the tool diameter.
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START STEP 3
Start a second ‘Job Ticket’ and configure as in the image above. Take care NOT to do the layer containing the holes again. There are screws there now! If you are unsure, consult a lab supervisor, but if you think you have got it you can proceed on your own. Press ‘Run’ again and start the milling process.
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TURN OFF VACUUM, DUST EXTRACTOR, TOOL When the process is finshed, turn of: -‐ the vacuum -‐the tool -‐ the dust extractor. Leave the compressor on for now, you need that one to be able to move the toolhead.
CLEANUP -‐
To finish up: -‐move the toolhead out of the way
-‐remove your part -‐remove the milling bit and put it back in the sorting box -‐remove the leftover parts of the plywood and put it in the trash
CONGRATULATIONS, YOU ARE DONE! If parts in this tutorial are unclear 28
or you have suggestions how to improve it, I would love your input at lieven.standaert@gmail.com
CNC-CUTTER CHECKLIST -‐Did you set
THE ORIGIN AND TOOL HEIGHT?
-‐Did you check if
THE DRAWING IS THE RIGHT
SIZE? -‐Did you select
TOOL 7 on the controller?
-‐Is
THE VACUUM & THE COMPRESSOR turned
on? -‐Is the
TOOL RUNNING ?
-‐Is the
DUST EXTRACTION SYSTEM on?
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