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Design for cost-effective AM
Component design for cost-efficient metal Additive Manufacturing Some companies approach Additive Manufacturing as a drop-in replacement for conventional manufacturing technologies. This approach, however, does not take into account the unique possibilities that additive processes offer and can result in parts that are not commercially viable due to cost. By designing parts specifically for AM, companies can reduce costs and improve efficiency while taking advantage of the possibilities offered by the technology. In this report, Olaf Diegel and Terry Wohlers look at the impact of good AM part design on machine operating costs.
The Additive Manufacturing of parts that have not been designed specifically for AM production can be very expensive. Industrial AM systems are also expensive, and part production rates are slow. An AM system capable of producing metal parts can cost from $500,000 to more than $1 million. One can optimistically assume that a metal AM machine will run about 80% of the time, which is around 7,000 hours per year. It is not uncommon for a return on investment (ROI) period for capital equipment to be in the range of two years. This varies from company to company, but for high-tech equipment, a two-year ROI period is a reasonable average for cost calculations. This means that the typical hourly operation costs of a metal AM machine can, depending on the value of the machine, range from about $37 per hour to $90 per hour. Using a “middle-of-the-road” hourly operation cost of $65 per hour, a part that takes ten hours to build would therefore incur a machine cost of $650. With metal AM, however, build times are often substantially more than this. In fact, it is not uncommon a part to take forty, sixty
Vol. 4 No. 1 © 2018 Inovar Communications Ltd
or even 100+ hours. If a part requires 100 hours to build, the machine cost, alone, is $6,500. This underscores the importance of finding methods to reduce the
build time whenever possible. It is also important to consider design methods that will reduce build time and material. The methods described in this article focus on metal Powder
Pre-processing and printing
Effected by design
Clean the AM system
no
Purge the system of oxygen
no
Preheat the AM system
no
Print the parts
Spread layer of powder (recoating time)
no
Print contour lines
yes
Print interior hatch patterns
yes
Remove build platform from machine
no
Recycle powder
no
Post-processing
Thermal stress relief
yes
Remove parts from build plate
no
Hot Isostatic Pressing
no
Remove support structures
yes
Heat treatment
yes
Shot-peening, surface machining, etc.
no
Inspection
no
Table 1 The main steps in metal AM, and the impact of part design
Metal Additive Manufacturing | Spring 2018
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