Cutting Plastic
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- čas přidán 8. 09. 2024
- Let's cut some plastic on the CNC mills! Machining plastics can be fun but it's a bit different from metal. Let's talk about the most common mistakes and take a look at a couple of parts being made.
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Hi Tom, it's amazing how we make assumptions about how things will machine, even although it's (potentially) the first time we use a material. A teacher once told me 'Mr. McIntyre, people like you are the reason people like me have a job. Hindsight and reflection are 2 of the most powerful enabling tools in your box'. He was a kind of Scottish Mr. Pete!!!! The video quality is superb, crystal clear. Thanks for sharing. Sincere regards. Joe.
+Joe McIntyre Hi Joe! I’ll have to admit that everything I assumed going in to cutting plastics was wrong. Slow down the spindle, speed up the MRR, be more aggressive; all opposite the usual course of action.
What did you think of the content format? I appreciate the feedback, sir. How was the audio?
Best wishes,
Tom Z
Tom Zelickman I think it's good to mix up the content,it allows feedback from you viewers (good or bad). The audio was ok, perhaps a bit noisy. (Being really pedantic). I think Abom and Brad are experimenting with audio. Ray's channel is a great example of a typical shop environment with lots of acoustic nightmare materials all around. Keith Fenner seems to have a good sound balance. What do you think? Kindest. Joe.
Tom, you have made it very clear to me that I will never be able to run any sort of CNC machine!! Although I find it fascinating, I just don't have the ability to understand the programming.
Great job, and the camera is Good!
Razor!
+Razor Works Hi Ray! I don’t believe that at all, sir. Practice and willingness to learn are all that it takes if you want to do something new. I started machining plastics on the manual machines long before using CNC. The Haas controller does look scary to use though, eh?
See you soon!
TZ
It's not as hard as it looks. Most controllers look very confusing and scary but it's not that bad.
That all makes a huge amount of sense Tom when really thinking about it. Very useful info for sure. Basically, plastic is just too plastic!!
I assume the flood flow is mainly for chip removal - although suspect too there are temp factors.
My main plastic work has been gross stuff like turned 3" nylon rod or Delrin rod etc (awful stringy chips of course that turn into a bird's nest!) - no major mill work (which anyways can't be CNC)
Camera looks great!
+ChrisB257 Hi Chris! We use mostly nylon here too. It can be stringy if you aren’t aggressive enough. Ask me how I learned that!
Spot on with the coolant. Definitely don’t want rubbing or recutting but the cooling and lubrication also helps.
Glad to hear the camera worked out alright. I’ve got a second one to put into use shortly as well.
Best wishes,
Tom Z
the O flute router/mill cutters do a good job of cutting plastic, same with worn out coated cutters
+daniel lyall I’ve noticed that about having a little wear on the cutters producing a better finish. Wasn’t expecting that at all, really.
Yer I found that out by the coated cutter being the only cutter the correct size it was a wtf, so I keep them for cutting plastic only
Thanks for the info. I’m a mere hobbyist and had great trouble making simple turned feet for a stool. Changed cutters, changed speed, depth of cut etc. finally got a set of four feet but terrible finish. The best finish I did get was in the bore with a good sharp knife edge tool. Inserts no good, tended to push aside and melt the material (Acetal)
I've found that with plastics it's good to have highly polished cutters - regardless of the type. You're spot on about them needing to be sharp too. Inserts worked just fine for me but the high polish was the key to that bit. Thanks for watching!
I really like the new camera. Great info on the plastics.
+David Rich Glad it worked out well. Thanks for watching!
Tom Z
I machine a lot of Delrin (Acetal) it seems to machine similar to aluminum. Another thing is plastic can be deformed easily in a vise, and if you are too aggressive it can rip it out of the vise. Especially on smaller parts.
+MCEngineeringInc Very good points! Acetal is great because it’s slippery but that also makes it a pain to hold on to well. Tighten the vise too much and it flexes. Found that out the hard way too.
Thanks for sharing!
Tom Z
How do you go about it? Any hacks?
I machine a good bit of lexan for smaller parts. You really have to use good sharp tooling as well. If are slightly rubbing, it will melt on you and load the tool up. Other than a higher ipt and slightly lower rpm, it machines pretty awesome. Some prototyping i do in lexan first and then aluminum, saves a little time and material.
I've not done any lexan before; good to know. Good point about RPM - I probably should have brought that up in the video. I made up for not slowing the spindle by increasing the cutting speed.
Thanks for the input!
Tom Z
Can we create snap joint with engineering plastic? Thanks
"if you rub plastic it melts" - and this is great because if you rub metal your tool melts instead ))
nylon is tricky, ABS is awesome to cut! I found it best with ABS to use a slow spindle rpm ~1000rpm is plenty and a fast feed rate and I get no strings and perfect wall finishes and edges where higher RPM tended to cause strings and heating that sheared the finish. on nylon is harder and doesn't work quite the same. I will have to look, but I did perfect my nylon parts with a good feed and speed rate that eliminated just about all of the strings, I hate second op or Clean up work on plastic, ruins the finished look!
+christopher polanski Agreed, hate doing the cleanup work. We aren’t using the right tool yet - still in the early production stage of that part. Haven’t done much ABS - will have to try that sometime!
Thanks for taking the time to share,
Tom Z
Hi, can you recommend any cnc machine for cutting, carving amber?
I think it was Robert Cowan who recently talked about cutting plastic. He mentioned end mills built especially for plastics, mostly two flute. But he did not say where he got them. Any comments on that?
I think the reason he went with 2 flute is likely to keep the RPM at the right range for the machine as well as chip evacuation. The RPM is important - you actually want to be going more slowly than you would think. You really don't want the chips to get compacted / recut because they heat and melt. Let me know if you have any other questions!
Sincerely,
Tom Z
new camera looks good!
+Jimmy Myers Thank you! Wasn’t sure how to work the darn thing...
Best wishes,
Tom Z
Very Helpful :-) Thank You!!
Thanks, Charles. Can’t wait to see what you come up with next!
Enjoyed....interesting....what are the two parts for...just curious....camera is fine!
Hi Chuck! The parts were for 2 different products that I supply component for; handles for heavy duty weight-lifting equipment and the other is a new, consumer-sized weight collar.
Thanks for watching, sir.
TZ
can you do the same without coolant?
Camera looks fine to me. At 2:51 it looks like your part is flexing all over the place?
+bcbloc02 Had to go back and rewatch that part a few times. I think what you are seeing is the thin strip that wasn’t removed during the facing op getting hogged out during that contour roughing pass. Maybe I’m not seeing what you saw?
Hope all is well, sir.
TZ
Thanks for the advice. How are you liking your GoPro. We got the Hero5 Session.
Still trying to figure out the GoPro really. I have a Session and a 3+ but just slowly getting into using them. Hopefully I'll get them going more over the next couple of weeks.
Thanks for watching!
Tom Z
Well Done!! :-)
Thanks, Charles!
Hi are you familiar with cellidor plastic
Go pro suite
To messy . Clean up time. Injection molding is the way for this.
I’d agree with you if there were thousands to make but for the volumes done it’s not financially an option.