Hi guys, I’m new to the site. I’m working on a commercial project for additive manufacturing, with CNC post process machining for close tolerance consistency. There seems to be little information about lay up / deposition speed for nylon or acetal. Anyone know where I might start looking?
I work with several industrial customers that use “3D Forging” The term used to describe what you’re looking for where a part is first 3D Printed using larger printers, then the part is placed on a CNC for a final clean-up pass. This is done almost exclusively in nylon 645. We design industrial hotends and extruders to handle nylons and acetal. The acetal must be non-glass filled. There are more ventilation requirements for acetal as well.
I’m not sure how well acetal would work. I don’t think it is a good injection molding material. AFAIK, it is generally cat into blocks, then machines, not extruded into molds. This would less me to believe that it would not 3d print well
@Eric_Moy , we I’M acetal, it’s common, but the biggest issue is the shrinkage. ABS is near .006"/1" shrink, and acetals are near .020"/1"!!!
@Tom_Martz that is really good info, I’m not particularly worried about the material specifics, but I’m glad to see that the technique is recognised. I’m putting a proposal together and need to estimate the 3d printing times and equipment costs. From what you say, the small machines I’ve looked at, although have the print volume, are not fast enough to be economic.
Actually, I can add some detail, I currently machine a 2.5kg billet of acetal to a finished part that is less than 0.5kg. 2hrs on a 5 axis CNC to throw away 80% of the material and occupying an expensive asset making a plastic cover.
@Tom_Martz we manufacture linear guidance slides and drive systems, all we need now is a commitment to a build project and we have a new thread each, LOL
@Tim_Page-Brown What is the max travel of your units? Also, max speed? Other than 2 large Delta’s, these units are rather large cartesian. (Those that we service) They operate at 100mm/s min and usually print at about 50mm/s . Most are bowdens running 3mm or larger line. Nozzles sizes are .82, .9, 1.0, 1.2 and 1.4mm typically.
As there will be a final CNC pass, retraction is not used.
@Tom_Martz longest belt driven module as a single unit is 6 metres, 2 modular units just manufactured last week were 32 metres long. Screw driven modules up to 4 metres (can be longer with 30mm or 40mm ball screw). Take a look at Hepcomotion.com, based in the UK, agents worldwide.