Fastest rapid prototype systems
Posted by Robert Kiser on Fri, Jan 30, 2009 @ 12:16 PM
There are two basic factors taken into account which define overall "build speed" of rapid prototype systems and 3D printers. One factor is "Total Build Time" and the other is "Post Processing Time". These two totalled together = Total part production time.
Total Build Time is an important consideration when studying the many rapid prototype systems on the market today. Many lay claim to being "the fastest", but you have to consider not only physical build speed that occurs on the machinery platform, but also post processing time (processes involved after the 3D model has finished building). If it takes 4 total hours to build a 3D model on a platform from one manufacturer, and 6 more hours after completion for cleanup, post curing, and other processes prior to shipment, the total build time is 10 hours. If the same 3D model takes 5 hours to build on another manufacturer's platform, but only takes 3 hours for post processing, the total build time is 8 hours. So overall, the rapid prototype system that gets the final 3D model into the shipping box sooner is overall faster and should be a strong consideration of yours.
A general rule of thumb is that a system that builds faster normally has poorer surface resolution than a slower building machine. This is because a faster rapid prototype system is building in thicker layers in the Z-axis (height), while slower systems generally build in thinner layers which allow a tighter compaction and finer surface quality. Slower, higher surface resolution rapid prototype systems make up for the tighter layering process by speeding an array of other processes that occur inside the system during build. Hence, a higher surface resolution system may only lag slightly behind a lower surface resolution system and advancements in technology now have these higher resolution systems building faster. But if post processing time of the faster system is greater than the post processing time of the slower system, end product completion is actually faster using the slower system.
I read a white paper once that listed build comparisons of rapid prototype technologies. I was amazed to find that technologies I knew were slower than others were listed as faster. The test had each rapid prototype system build the same part at the same layer thickness (in this case .012" thickness), started at the same time, then a winner was picked. Problem I found is the fact that all rapid prototype systems don't build at the same layer thicknesses. So of course, the results were skewed. Also, average post processing times were not taken into account. I then did my own notes and found that systems that actually built slower, but had a faster post processing time associated with them, produced the end product faster, much faster in many instances.
So when you look at purchasing a rapid prototype system, ask for fair comparisons of technologies against others. Ask in detail about the post processing procedures. Ask yourself if you can sacrifice surface quality to gain speed. Every person who I have spoken with that purchased a low resolution rapid prototype system has said: "if I had to do it all over again, I would spend the money on a high surface resolution machine".
