[inov8r]

I have been shopping for a mini mill/engraver that will do the job that I have been doing on my Deckel pantograph. I have included a couple pictures as an example of what I do. The coin and electrode are about the size of a half dollar. I use a 15 deg. single lip cutter with a .002" and .004" tip. The design is only machined .007" deep, but I need to retain the fine detail that I get with the pantograph. At the present time I am machining into Graphite, but would like the option to do copper electrodes as well. I am looking at the pcnc 770 with its 10,000 rpm capability. Not having any experience machining electrode copper, I am a little leery whether these rpms are adequate. My Major concern is whether the accuracy improvements in the series 3 machines, will give me the performance and results I need. Well that is my story. Any thoughts, info, recommendations or preferably personal experience that you could give on the subject would be greatly appreciated.

Attachment 218474

Attachment 218476

[Steve Seebold]

What is the width of the letters? The outside can be done with an end mill, and it looks to me like a lot of the inside can be done with an end mill as well.

I think the PCNC770 will do what you want to do with ease, and you can actually set up several parts at one time and walk away while the machine does its thing. Then you come back after some time, change tools, push the start button again and leave.

I have a PCNC 1100 and I have some jobs that require +/- .001 tolerances, and I can run that all day long. I haven't had the need to run anything any closer, but I think +/- .0005 is possible. The best circle I have managed so far is about .0015 out of round.

I have said before, if it's closer than +/- .005, I don't want it. I'm supposed to be retired, and I don't want to work that hard any more. And yes, I am lazy.

[Ken Gastineau]

I have a PCNC 1100 Series II and use 15 deg. single lip cutters with .005" points on a regular basis. Of course I have to use an auxiliary spindle to improve machining speed. I use a Taig ER16 spindle and motor which has a max 10,000 rpm. I am interested in incorporating a 20,000 rpm spindle in the future.

Most of my work with these small cutters has been for carving waxes for jewelry model making. I have however successfully machined Sterling silver (pocket engraving tiny letters)and 01 tool steel with it. I too started with a manual industrial pantograph (Gorton 3U), but have not used it since I bought the Tormach.

So in my experience a 10,000 rpm spindle is fast enough to be in the game so to speak and an auxiliary high speed spindle for faster speeds and feeds is easily managed with these machines.

Positional accuracy has not been an problem for me, nor has spindle runout. Those are two key issues when using such small cutting points.

[MichaelHenry]

There is also the Tormach speeder, which would give you up to 30,000 rpm on the PCNC 1100. That's a better solution if you can get by with one tool, but there are ways around that

What is your tolerance on cutting depth? As Steve says, the Tormach is probably +/- 0.001-in on Z repeatability, possibly a little worse.

FWIW, I use a 1/8" V-bit with 60° taper and 0.005-in tip to engrave letters about 0.010-in deep in brass and that has worked well for me.

Mike

[inventor1227]

I have the Tormach 770 series 3 now. That amount of depth I did attempt on the 770 it did the engraving sign, but my flatness on my set up wasn't correct. I have the engraver tool they sell, but I'm using the small mill bits instead. The engraver needs more adjustment then I have patience for. You have some nice intricate parts there. I agree with Steve mini mill bits will get you this intricate detail. I went to their CNC class and actually used this mill before I bought it. They never ran it at 10,000 RPM. They said, they never do. Cheers

[Bryan Turner]

My 770 spends most of its time at 10,000 RPM, no issues at all (though I'm still under 100 hours on the spindle).

I don't see any issue cutting this piece on the 770, the issues will all be in setup: flatness of the part in fixture, setting the z-height of the spindle to the part, runout of the collet, etc.

For the measurements, I splurged on a Haimer 3D (analog). It easily measures backlash of any axis, flatness of any setup, and set z-heights into the tenths (need the analog version for this precision though). Buy an extra tip.

Haven't had need to measure runouts at the precision you're looking for, but from my reading the TTS ER 16 or 20, with a slightly-annoying technique called 'clocking' to find the best collet to spindle alignment should get you all the precision you need.

--Bryan

[Steve Seebold]

Here's a picture of a plaque I made for my mother-in-law when we buried her. It's 4 X 8 X 1/8 inch thick brass.

I ruffed it with a 1/4 inch 3 flute end mill then I finished the raised lettering with a 1/16 2 flute end mill, then I took the corners out with a .010 2 flute end mill. The raised letters are .030 deep.

The bible verse was done entirely with a .010 end mill running 5,000 RPM. The depth is .010 total depth and I took that at .0025 DOC, so it took a long time to do it.

The whole project took almost 12 hours.

Then I had to sand the cutter marks out of it. I started the whole process about 10:00 AM and I finished around 3:00 AM.

[philbur]

I do engraving from time to time, although as yet nothing that small and detailed, so I was interested to test the 1100. Below is some simple text engraved on a piece of scrap brass. The disc diameter is 28mm the text height (outside height of the Z) is 1.6mm. I used a 30 degree single lip carbide engraving bit - 0.1mm tip - mounted in a TTS collet chuck. Speed was 5,000 rpm - feed 30 mm per minute - DOC 0.03mm + or - !!. The font was just a simpe single line font, hence the segmentation. No special set-up just jumped in and did it to see how it would handle it.

Phil

[inov8r]

I would like to thank everyone for their insight and input. You have all been very helpful. As a side Question, What software would you recommend for two dimensional work like this?

[philbur]

I've never used it but Vcarve Pro seems to be very popular and highly rated.

Phil

[Steve Seebold]

As a side Question, What software would you recommend for two dimensional work like this?

I use GibbsCam. I had it when I had my shop and the guy who bought the shop wanted to use Mastercam so I brought my Gibbs home with me.

I was going to retire when I sold the shop, but that only lasted about 3 months before I had to go get a job. Then the economy took a dump, and the part time guy (me) got laid off. That happened about 3 times before I decided heck with this and bought a machine to put in my garage.

I have never looked back.

[BOATDUDEGUY]

X2 ON THE vcarve
cheap as dirt and just as simple to learn

[BOATDUDEGUY]

I have been shopping for a mini mill/engraver that will do the job that I have been doing on my Deckel pantograph. I have included a couple pictures as an example of what I do. The coin and electrode are about the size of a half dollar. I use a 15 deg. single lip cutter with a .002" and .004" tip. The design is only machined .007" deep, but I need to retain the fine detail that I get with the pantograph. At the present time I am machining into Graphite, but would like the option to do copper electrodes as well. I am looking at the pcnc 770 with its 10,000 rpm capability. Not having any experience machining electrode copper, I am a little leery whether these rpms are adequate. My Major concern is whether the accuracy improvements in the series 3 machines, will give me the performance and results I need. Well that is my story. Any thoughts, info, recommendations or preferably personal experience that you could give on the subject would be greatly appreciated.

Attachment 218474

Attachment 218476

may i ask what are these engraved electrodes end up doing

[inov8r]

may i ask what are these engraved electrodes end up doing

I use them to burn (EDM) a tool steel (A2) die which in turn mints a coin like the one I've displayed.

[BOATDUDEGUY]

very kool

[kstrauss]

Actually Cut2d from Vectric (the people who also make Vcarve Pro) will probably do all that you need for this sort of work and is much cheaper. You can download a free version and try both before buying.

[tbaker2500]

Cut2d or VCarve. Use it all the time, perfect for this.

[inov8r]

Cut2d or VCarve. Use it all the time, perfect for this.

If you don't mind me asking, What machine do you use?

[kstrauss]

PCNC770 with Cut2D. The software is easily learned and reliable but the paths that it generates for pockets are definitely not ideal.

[tbaker2500]

I use it on a series 1 1100. I do a lot of fine work, certainly good to 1 thou.