If the Space were to permit cutting plastics on the machine, what kinds of plastics would people want to cut?
Phenolic, acrylic, foam? Foam would be really nice for tool inserts (canāt cut pockets on a laser).
Acrylic, sign plastic, more acrylic
Solid surface!!!
Iāve always wondered what the hell this stuff is, I finally looked it upā¦ Itās plastic! Well, kind of. Lots of other stuff in there too. Maybe this is a material we should evaluate as to whether we allow or not.
So far:
Acrylic
Polycarbonate
Sign foam (eurethane, etc)
Phenolic
Delrin
Polypropelene
Polystyrene
What else?
(Dibond probably more defined by aluminum skin, another inquiry of its own)
Iād love to be able to cut some DiBond. If anyone is wanting to actually check some out, Iāve got a couple chunks of PolyMetal (another brand of DiBond) in storage at the space for my splitter build right now. Iāll say that Itās pretty unlikely that weāll get it on the CNC though, as the metal does tend to chip off and would certainly cause issues.
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I think the biggest issue to tackle is going to be debris control and cleanup anyways.
E: People donāt even brush out the collets and bearing nuts, much less remove pitch and resin when it builds up. Plastic melts when it gets hot and, worst case scenario, can ruin the spindle. The cold gun is going to help in the sense that it will blow away the chips, but that can cause contamination issues in the woodshopā¦
Very true, but not unconquerable I think. Some experimentation is going to be needed, and because of the large number of variations in material, some review process may be required (something like a bit checkout or whatever). Quite a few are abrasive.
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Some plastics machine very well, like Delrin, HDPE, etc, and are very forgiving of machine cutters, but others, like acrylic, are brittle and really need end mills that are designed for that material to get the best results.
Then there are some materials, like ABS which are very susceptible to melting while being cut.
Given the wide range of potential plastics that could be use, I suspect it will be a fair bit of work to get VCarve programmed with all of the possible feeds and speeds as well as getting the cutters appropriate for the materials.
Then there is the training that will be needed to get people to know which cutters and settings are appropriate for which materials.
Milling plastic would be a very useful additional capability; however, it will be a fair bit of work to get it all done. I am willing to help, particularly with pulling together feeds and speeds as well as identifiying appropriate cutters.
As to a list of plastics, I will add my personal favorite; nylatron
Here is some useful information I found that might help
https://www.onsrud.com/files/pdf/MechPlastic.pdf
http://www.curbellplastics.com/technical-resources/pdf/plastics-machining-guidelines.pdf
https://www.plasticsintl.com/documents/Guidelines%20for%20Machining%20Engineering%20Plastics.pdf
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As with a lot of things, the devil is in the details. Setting feeds and speeds is actually the easy part, since its a simple engineering exercise. Determining how to clear chips, and avoid damaging wood that comes in contact with chips, buying and maintaining an inventory of appropriate bits without bankrupting the woodshop budget, etc. are where the work really lies.
But knowing what users want to cut is step 1!
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HDPE does machine well. It would be a great starting point.
A prosoed possible solution: If and when plastics are allowed, maybe it might be wise to have āPlastics Onlyā week once a month or ever 6 weeks. A separate spoiler board could be used and changed out and clean up for that week would be more thorough than on an individual basis (shouldnāt be, but probably is reality even for wood workers).
A short supplemental training class in order to cut plastics would have to be attended by persons already approved for using the MultiCam. The class would go over the approved plastics, unique clean-up routines, which cutters (separate tool box), etc. This would allow use for plastics, not on an everyday basis, but would open the tools up for higher usage. By limiting it to select open periods only cross contamination would be greatly diminished with wood projects, which is a very reasonable concern,
A lot of projects require plastics, many larger than the lasers allow or are permitted to be used on the lasers.
IMHO, this class should cost additional money. There is certainly additional tooling and possibly additional dust collection infrastructure. I donāt think it would be advisable to have a large drum of mixed-material dust and shavings (and it may even be forbidden from a fire risk standpoint). Thoughts?
I concur that a class on using plastics with the router ought to be an additional cost. I would also disagree with Davidās characterisation that it would be a āshort supplementalā training. While it might not need to be as extensive as the original class, it would still require the coverage of substantial material in my opinion. There are a lot of plastics available and how they are machined varies a fair bit. Including some that really canāt be successfully machined.
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I was addressing more access to the machine - not cost of classes is up to the instructor/committee/etc.
Regarding the mixed drum issue, I noticed yesterday that there was a second portable vacuum system in use. The week in my proposal when doing plastics it it could be connected instead of the fixed system, that would resolved that concern.
Short, meaning not as long as the CNC Router original training since the basic operation of the machine, how to use VCarve, practical machine testing, etc. has been taught and demonstrated. The Plastics training would focus on the characteristics associated with machining permitted plastics, what cutters, and items such as the collection system change over.
One thought might be to host an āadvanced CNC Routerā class, where the fundamentals of feeds and speeds, advanced materials, and advanced topics in vCarve Pro mit be taught, as a prerequisite for cutting anything other than wood.
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