Hi All, Yep, I just signed up today as I have a question for the experienced and or staff. Is it possible to make a steel master mold (from Shapeways) to be used with a plastic injection molding machine? Basically, it's for minature robots/battlemecha, for fun. If anyone has done it, or knows what's required, I've love to hear your stories. Thanks Foxi-5 (Mech Eng)
I have a lot of experience with both 3D Printing and Injection Moulding. Feasibly, it'd be possible to make a tool from the SS, but you'd need a lot of post machining in order to make the cavity smooth enough to eject the moulded part properly. You'd also need a mould base as well, or at least an injection moulding supplier that allows you to supply the inserts to their library of tooling bases. As the LaserForm process isn't particularly high resolution in the first place, the better idea is to look into silicon moulding. You take your original master part (made in one of the higher resolution machines), encase it in a mould of silicon, and then cast polyurethane plastics into the cavity. Cheap, effective, easy. The tool may only last for 20 shots, but you could make many many silicon tools before even getting close to the sort of costs you'd be looking at for doing a 3D Printed/Post Machined SS tool.
I've tried. It's a nightmare. As part of the SS printing process, there is a step that results in either a volumetric shrink or expansion of the part (think green forming ceramics and then sintering). Everything will be off by a few percent and every surface will need to be machined. You're far better off just CNC machining the part. If you're absolutely dead set on using a printing process you're far better off using a DMLS process. Hopefully Glen will pop in and add some further insight.
Thanks guys. Yep I have looked at Silcone Molds, and am just a bit iffy on the output, plus my haggard attempts in the past. I'll take a look at Laser Sintering companies before I look at silcone again. I've been impressed with some creators making home versions of them. If there is a lot of post work for cleaning up the surfaces, then Shapeways steel probably would be a bad idea for me. I appreciate the insights!
You will need to polish every surface for injection molding if any printing technology is used. DMLS will give you a "cast" type surface which will need to be polished. There is no free lunch here. Quality molds go for $10k+. Injection molding is a volume production technology. If you don't need the volume don't use it.
Foxi states the parts he wishes to make are for "fun" so I will assume these "minuatures" are intended for use as gamepieces or shelf sitters? So high dimensional accuracy might not be an issue at all? What sort of production volume are you talking about; dozens, hundreds, tens of thousands? No question about post production finishing of mold surfaces from any print technology and even CNC produced molds often need hand work. DMLS might yield better dimensional accuracy but it will also cost about 8-10X more than the SW ss and you will still be left with the hand finishing work. Maybe best just to print these things directly in some of the hi-detail plastic materials? I also believe there are Asian sources for relatively low cost, short run (100's-2500 pieces) plastic injection molding services. Even still, your out lay would be $1000 or more per mold. -G
And at all with a low cost mould you haven't the guarantee that it's has the size you real won't becaus of the material shrinking... So I think, it doesn't work in the first time, and would cost you a lot... I a lot of people have the problem to get a low cost injection mold. At all in the moment for my production the material is the problem... The details are okay but the material at shapeways is not real lucent like the original one... would like to see how the squishy material works for us... specially in different colours.. https://www.shapeways.com/blog/archives/1163-We-Found-a-Squis hy-New-Material-to-3D-Print-Tell-Us-What-You-Think.html
Thanks all. Yep, I found out from the makers that laser sintered items do require a fair amount of work to make things clean. Looks like that's the wrong direction for protoypes and small runs. @ GlenG Unfortunately, dimensional accuracy is the 'most' important thing. Being the joints and connectors. I wanted about 20 initially, and if proven to be a winner, many more, probably in the hundreds. When you say print in high detail accuracy (refering to materials). Would that be more affordable to go for something like the Ultimaker and just print them from that?
I know some people have been able to make "pop apart" components and I think the WSF material was used for this. But any of the more flexible materials should work for this sort of thing. Just realize that if you are looking for some process to produce hi resolution, high tolerence, shiny, colored plastic parts 3dp is not going to meet this requirement. In the grand scheme of things, 3dp is still in it's infancy. It's up to you as a designer to understand the limitations and also to exploit the capabilities to the max. -G
@ GlenG. Yep, infancy, sure looks that way... Just wish I had the time to tinker, being an engineer and all. Oh well, 3D Systems have just wooed me with their latest material, so I'm going to do another print in that for the moment...