The tool master that manages my main workshop services supplier once told me that he much prefers to use high speed steel for some plastics instead of carbide.

 

I use carbide, because it is convenient, and with the grinder shown previously, one wheel is diamond. As I don't do CNC, I also re-sharpen my cutters, especially solid carbide boring bars for small holes.

This morning I came across a nice article comparing swelling and stability of a variety of polymers for 3D in various solvents, including water. POM (Delrin) looks pretty good: https://www.nature.com/articles/s41598-019-56350-w Of course it is not perfect, and at present, it is not available as a photopolymer.

 

Yes, it does produce a long chip, but compared to nylon, for example, I found it easier to work.

I use mostly HSS and use a big chip breaker in them, the way I was taught many years ago, works great on most things but on POM or Nylon the chip comes off in one long piece, I have a couple of times emptied all of the other metal chips in the chip pan from the long plastic chip going first into the pan and then wrapping around the part. This is while hogging material off taking 1/8" or more per side and a real coarse feed.

Your carbide cutters, compared to a HSS ground one are dull. So that may be why you aren't having as much trouble. I very seldom use carbide, other than on prehardened stuff, like 4140.

 

in piece of Molybdenum

Moly cuts like cast iron, makes a real similar chip. It's one of the most expensive, easy to cut metals I ever worked with.

 

I use mostly HSS and use a big chip breaker in them, the way I was taught many years ago, works great on most things but on POM or Nylon the chip comes off in one long piece, I have a couple of times emptied all of the other metal chips in the chip pan from the long plastic chip going first into the pan and then wrapping around the part. This is while hogging material off taking 1/8" or more per side and a real coarse feed.

That seems more aligned with my comment about needing a good grinder than your comment here about CNC:https://forum.allaboutcircuits.com/threads/the-right-to-repair.127119/page-8#post-1558729 Which is it? Do you need a good grinder or not?

I use both HSS and carbide. I am also lazy and use carbide when its readily available and does the job. I am no machinist. One place I worked had real machinists who could sharpen a milling cutter almost as good as new, free hand. I couldn't tell the difference between what he did from a drill bit for an odd size mill I needed and what my Polish/Israeli mills did.

 

That seems more aligned with my comment about needing a good grinder than your comment here about CNC:https://forum.allaboutcircuits.com/threads/the-right-to-repair.127119/page-8#post-1558729 Which is it? Do you need a good grinder or not?

Carbide tooling is more helpful in CNC. for a couple of reasons, a CNC machine(not home built) is built more rigid and the spindle and feeds are much faster than conventional machining. Insert carbide tooling is made virtually the same shape and size to a given standard. Off the top of my head I don't remember who's standard, I'd guess ANSI but could be wrong. This allows CNC to work in concert with CAD. The differences of you versus me grinding a HSS tool won't work in CNC because it doesn't fit what is in the CAD algorithm(not sure if that is the correct term for how CAD and CNC work together).

Even tool holders are under this same standardization in CNC. Manual machining you can vary how you angle or position a tool to allow what you've ground to do the job you need to do. Not so in CNC, those tool holder have to be used in the machine the way they are made. If you add or subtract even a little from what the program expects things to be, you just scrapped the work. This is also why as an old fart analog/manual machinist it's hard to accept a CNC OPERATOR being called a MACHINIST. Most places they don't even program the job, or any place I'm familiar with. They have people in an office doing the CAD programing from what is on the blueprint.

 

I use both HSS and carbide. I am also lazy and use carbide when its readily available and does the job.

If you look at your carbide inserts you will see that they are not sharp like a ground HSS tool. They have a small *land* between the actual cutting edge and the chip breaker. This land and the higher speed in a CNC machine situation is what lets them cut good and not chip. And is probably what the difference is between you experience with Delrin and mine in lathe work. HSS shears the chip and insert carbide smashes it off.

 

WALMART.com alert

This is insane. Creality 3D CP-01 3D Printer/CNC/Laser Engraver for US$51.99.

https://www.walmart.com/ip/Creality...CNC-Milling-Cutting-DIY-Carving-Eng/991314698

Edit: I suspect someone made an error in the pricing, maybe it should read $1151.99???

 

WALMART.com alert

This is insane. Creality 3D CP-01 3D Printer/CNC/Laser Engraver for US$51.99.

https://www.walmart.com/ip/Creality...CNC-Milling-Cutting-DIY-Carving-Eng/991314698

Edit: I suspect someone made an error in the pricing, maybe it should read $1151.99???

​

​

apparently, buyers get a $2 Tackle box if there is a misprint or they realize something is wrong with the order. Then they charge for a return and buyer pays postage back to wherever (not USA).

I read three reviews regarding tackleboxes.

Ordered a lightweight sleeping bag and received a confirmation with an image of the sleeping bag and accompanying text stating that they were sending a tackle box. Immediately responded with written request to please clarify the disparity. Did not get a reply and later received a cheesy six compartment tackle box .​

They have 50% of reviews at 1-star

 

WALMART.com alert

This is insane. Creality 3D CP-01 3D Printer/CNC/Laser Engraver for US$51.99.

https://www.walmart.com/ip/Creality...CNC-Milling-Cutting-DIY-Carving-Eng/991314698

Edit: I suspect someone made an error in the pricing, maybe it should read $1151.99???

I went ahead and bought one for fun. I'll let you know how it works out.

 

I went ahead and bought one for fun. I'll let you know how it works out.

I hope you get it.
A couple of years ago, I purchased 1000 power FETs for 5C each, and the store honored the order.
I am sure it was a typo, but they arrived anyway. So, you never know! You may become the proud owner of a 3D printer

 

You may become the proud owner of a 3D printer.

I already am. At $51 (plus reading some reviews), I'm not expecting much. I bought it purely out of curiosity.

I half expect I'm going to receive a print head or some other replacement part rather than an actual printer.

 

I went ahead and bought one for fun. I'll let you know how it works out.

Maybe you'll get the free tackle box for your bait?

Just noticed on checkout this:



Notice the "sold by".

 

Maybe you'll get the free tackle box for your bait?

Just noticed on checkout this:

View attachment 227041

Notice the "sold by".

He's possibly related to either you or me.

 

I already am. At $51 (plus reading some reviews), I'm not expecting much. I bought it purely out of curiosity.

I half expect I'm going to receive a print head or some other replacement part rather than an actual printer.

It was worth a try. At least the return/refund process is painless via the Walmart app...

 

It was worth a try. At least the return/refund process is painless via the Walmart app...

Now we know. Thanks for posting an update.

 

I've been cleaning my shop's clutter and throwing things away, and I discovered a few prints I made a couple of years ago with my Epax printer, which works with liquid resin. The prints in question have become almost perfectly transparent (prints normally look kind of milky when they're pulled out of the printer) and are much harder and tougher than prints that I made a few months ago.

That tells me tons about the time that it really takes for the resin to thoroughly cure.

 

I've been cleaning my shop's clutter and throwing things away, and I discovered a few prints I made a couple of years ago with my Epax printer, which works with liquid resin. The prints in question have become almost perfectly transparent (prints normally look kind of milky when they're pulled out of the printer) and are much harder and tougher than prints that I made a few months ago.

That tells me tons about the time that it really takes for the resin to thoroughly cure.

Any dimensional drift in that time?

 

Any dimensional drift in that time?

Good question. I do remember the parts being quite tall (for the printer) and they were about 3% taller than intended when they came out.

I'm gonna check and get back to you.