Plastic Prototype CNC Turning on the DMC Lathe

[@tarkka]

Somebody should have a word with the engineer who put a +/- .0005 tolerance on plastic. Props to you for being able to hold that!

[@zalamachineshop]

Haha he said he simplifed it for me.

[@spazzywhitebelt]

We talked with a plastic supplier once and they jokes if it's not in tolerance push or pull the part until it is. But really though it's difficult to measure a soft material

[@weldmachine]

It,s good of you to take the time to make video,s like this for us to watch. Making video,s myself i understand the time it takes to make a fairly simple video. It is very much appreciated by the people who follow you. Thanks for the video,s. Peter.

[@zalamachineshop]

Thanks for watching Peter.

[@precisioncomponentllc1820]

it's snowing in june! nice work!

[@MajklskiLP]

Nice work

[@engineeringari9136]

Goodjob

[@71brp84]

I'm sure the diameters are correct at the point they come off the machine, but what are you doing to stop creep, so they're still in tolerance an hour/day/week later?

[@weldmachine]

It,s a reasonable question. Especially when machining Acetel. In the case of this part. Do all the roughing out. Take it out of the Lathe come back the next day. Reset it in the Lathe do all the finishing. More important when holding tolerances like this. The other thing is with the size of this part it would move around a fair amount after removing so much base material. But Not important i guess i am Not doing the job.

[@zalamachineshop]

The way the video showed it worked great. You have to consider how to hold it best. The way I did it I did not have to let the part rest. Usually parts don't change all that much only maybe when you squeeze it too hard. I go directly to finish size on the machine and haven't had much trouble with parts changing sizes at all.

[@diegoaguilar9219]

How much pressure was your chuck set at, Doesn’t that stuff get crushed?

[@danielkalinowski5157]

probable between 5-8 bar.

[@Nady87full]

Good job 👌🏻❗️

[@tomassabov5756]

hi! what is the material? and what speeds and feeds do you used guys? it woould rly help me. Thank you

[@zhangmax3646]

ABS maybe fire proof ABS

[@JonasDM46]

Question from a noob here. When you flip the part, where is the workpiece zero, how do you get the part at the right length?

[@zalamachineshop]

I always have my zero on the front face of the part. On side 2 I always take a test facing cut go up only on X and measure the thickness of the flange in this case. Calculate how much extra material I have on the face and set my G54 Z.

[@spazzywhitebelt]

Or if you're using soft jaws you can cut a face into them to act as a stop to set the end of the part against

[@weldmachine]

The biggest pain about CNC Turning. Is the Endless amounts of Soft Jaws you need, and finish up owning. Of course they can be Re-cut to another size ?? But then you risk Re cutting a set of jaws that you need at a later time. Thanks for the video. Peter.

[@zalamachineshop]

Yea I have many sets but they've been cut to shit. I'm planning on making new soft jaws soon. I'll take a video.

[@weldmachine]

@@zalamachineshop Thanks for your reply. I am sure you must own a few sets of soft jaws, LoL. They are a necessary evil of CNC Turning ??? Thanks again. See you on the next one. Peter.

[@Fischer977]

Is this machine is the one that have been crashed? You didn't upload a video of how did you manage to overcome the problem

[@zalamachineshop]

Yea it is. The repair took 3 weeks and didn't make for a good video. Too much cursing and swearing.

[@dontfeelcold]

Acetal, once heated past approximately 250degC, releases formaldehyde gas.

[@weldmachine]

Even at temperatures below 250. It,s Not the best stuff to be around. I would not want to be the guy cleaning out the swarf after this job. You could call it the Bee Sting effect ? It will Not harm some. But can cause some long last side effects to others ??

[@zalamachineshop]

Ahhhh that's why it smelled so sweet.

[@nisio_freak]

Why did the chips of POM become like powder? Does the material include glass fibre?

[@raider1628]

how long of in endmill did you have to use for the counter bores??

[@zalamachineshop]

Not too long. We have extensions for extra reach.

[@Davemcmasters]

What are they for?

[@dws_damiansworkshop]

Hey man.. what happened to your crashed cnc lathe? Could you repair it? By the way, the Thumbnail of this vid made me think the part was a lot smaller than it is.

[@zalamachineshop]

This is the crashed machine. Never took a video because it was 3 weeks of pure frustration. This plastic job is one of the first more precision parts after the crash. Minor issues here and there but pretty good overall.

[@qualified_monkey8813]

O, fajnie widzieć coś nowego. Jak poszło z naprawą głowicy po dzwonie?

[@zalamachineshop]

Maszyna OK zajela 3 tygodnie naprawic. To pierwsza powazna robota po tym dwonku.

[@nickkeith5683]

Why the VNMG for OD roughing? I would have gone with a CNMG with .004 nose radius.

[@IkkFedt]

Deeper debth of cut with a VNMG/VBMT. Since it's plastic, you can afford to use the whole cutting edge

[@danielkalinowski5157]

probably a better chip breaking geometry on that style of insert, i have cnmg inserts from a typical company and they're really bad.

[@nickkeith5683]

My usually is a CNMG with a sharp radius. Usually take .250 at .020 for roughing with no issues.

[@dwighthickerson6850]

Very impressive! Someone that knows how to program a lathe on you tube the way I do at work! What I sets were you turning with? I turn 4140PH most of the time and have trouble turning 6/6 nylon .

[@zalamachineshop]

Yea I much prefer 4140 to most anything. This cut nice but I struggled with many different polymers.

[@robertregalado1015]

Lots of secondary work after the lathe with the flats and bolt pattern. I thought the lathe would do it all...guess not.

[@zalamachineshop]

Exactly just standard 2 axis turning.

[@alexgregg2466]

Love a bit of acetal, I've got 220mm diameter black acetal to machine soon, only 50mm long billets though 😞

[@kapitandOOpa]

8:04 dobrze że to nic twardego bo by było po płytce

[@maras12322]

Moim zdaniem to nie było uderzenie w materiał tylko wióry które trzymały sie tam dzięki sile odśrodkowej sprawiły takie wrażenie