PCB Milling

[jrm850]

Howdy Folks, It's been a while...

I tried to add this to a great old thread about pcb making but it was locked and I just had to share this.

I finally bought a cnc mill and thought some of you that were considering one might like to see what they can do. I'll never etch a board again This a a tqfp 44 footprint and the pads are 1206s. Every via is drill dead nuts centered on both sides and I'm still using the same .028 carbide drill after 7 boards. Lovin' it.

 

[toothfairy]

Looks good, what brand of CNC mill are you using ?

 

[jrm850]

It's a Tormach 1100. I added an adapter plate to the spindle to hold a Bosch Colt router and use a precisebits collets and 60degree V cutter with a .005" tip. This was cut at 35000rpm with a 30IPM feed rate and a .004 depth of cut. The top side of this board takes just under 11 minutes to cut if I just leave it as isolation routing.

 

[toothfairy]

Cool, I assume you write your own programs, CNC is the way to go, I have a HAAS Mini Mill going now here at work. although I'm making door knob parts.

 

[jrm850]

Lucky You. The Haas was what I wanted, but the wallet said otherwise. I'm limited to 90IPM and 5100rpm but otherwise it's a heck of a value.
I've switched to Designspark from eagle to produce the circuits since CraigHB pointed it out to me here about a year ago. CamBam imports .gbr directly so it's as simple as selecting all of the polylines and doing a single outside profile MOP. For these small pitch footprints I found that .014" cut width with a .8 stepover works great.

For workholding I milled an aluminum plate with a small -x -y stop and just use a few drops of CA to glue the board to the aluminum. It holds amazingly well. I cut the board outline in the first step so I have a precisely dimensioned board. This is important for alignment when you flip the board. I was just drilling the mounting holes ithrough the board into the plate and using ground dowels for alignment but you have to have symetrical mounting holes for it to work. When you are ready to flip the board just squirt acetone between the pcb and aluminum and pry it off.

 

[jimbalny]

ooOoo.. how cooollll.. i want one

 

[toothfairy]

jrm850
Keep up the good work and good luck to you.

 

[DonG]

Jrm, been drooling over the Tormach for a while. How do you like it and how much fiddling was involved in setup to get accurate and repeatable results?

 

[zoiDman]

It's a Tormach 1100. I added an adapter plate to the spindle to hold a Bosch Colt router and use a precisebits collets and 60degree V cutter with a .005" tip. This was cut at 35000rpm with a 30IPM feed rate and a .004 depth of cut. The top side of this board takes just under 11 minutes to cut if I just leave it as isolation routing.

Very Cool.

That must have been Fun to watch when you cut it.

I have written a Lot of CNC Code for VMC's. Can't say that I have written Much with a Speed and Feed of S35000/F30. Most of the Machine Spindles I write for Max out at 10K

 

[debook]

Oh man that is cool...let me know when you are taking orders!

 

[classwife]

...you will see Registered Supplier under his name when he has registered and is taking orders

 

[jrm850]

I'm really happy with the mill so far. The size fits the lab and it's singe phase. You can move it into place on a pallet jack.

Mine got dinged up in shipping so it was a little difficult to tram. In fact, it's still not trammed to within spec, I just haven't had any time to fix it. Other than that, it is a breeze to get going. I may have had a little head start because I have 20 yrs experience on a manual, but to tell you the truth it's apples and oranges and I don't think it's a huge advantage. There are plenty of owners willing to help you if you get one.

About the heaviest work I have done on it so far is cutting that Bosch bracket out of 1" 6061. It didn't struggle at all and the rigidity appears to be similar to my manual J head. I have done some 3d profiling in Delrin and I am really happy with the surface finishes. I really wanted a Haas TM1 but just couldn't handle the price tag.

Jrm, been drooling over the Tormach for a while. How do you like it and how much fiddling was involved in setup to get accurate and repeatable results?

 

[zoiDman]

... I have done some 3d profiling in Delrin and I am really happy with the surface finishes. I really wanted a Haas TM1 but just couldn't handle the price tag.

Does your mill run off stand alone G-Code programs? And if it does, is the code a FANUC style Language?

 

[jrm850]

It uses Mach3 as the controller and does use standard g code. Any CAM program will output usable code.

 

[5cardstud]

Wow I am impressed. That is so cool.

 

[zoiDman]

It uses Mach3 as the controller and does use standard g code. Any CAM program will output usable code.

Sweet...

The nice thing about FANUC is just about Every CAD/CAM package out there has a Post to make FANUC Code.

 

[nicotime]

Nice jrm....I wouldnt mind having a Haas..or yours...in the garage either. Before my back gave out I was running and programming for a Haas VF-4, 2 VF-OE's and a HL-1 lathe...loved them. Do yourself a favor and make sure to have a good certified machinist level (at least .005/12") and check the level often. Check it with X and Y centered then at all four corners of travel...makes a big difference. I made parts for a metrology equipment manufacturer..laser tracker..probes, spindle analyzers and so on. Basically we made the equipment that checked the machines that were making the parts for! About every month or so we ran checks on the machines and they could tell right away if one was out of level. Its a PITA but its worth it if you want accuracy and less wear and tear on your machine.

Have fun man...I envy you ...I'm down to a hacksaw and ballpeen hammer now!!

 

[jrm850]

Thanks for the tips! I have a Starrret machinist level that I've had for about 20 years which if I remember correctly it is .006TPF. The machine base that comes with the Tormach is probably my least favorite part. The company suggests that I fine tune the tramming by shimming the base of the mill between the mill base and stand, but the stand is not nearly sturdy enough to have any lasting results.
I love the HL-1 but it's probably too much for my shop. I've been keeping my eye out for a used TL-1 though. In the mean time I'll have to stick with the old 13" manual or play with using this Tormach as a vertical lathe for small parts.

Nice jrm....I wouldnt mind having a Haas..or yours...in the garage either. Before my back gave out I was running and programming for a Haas VF-4, 2 VF-OE's and a HL-1 lathe...loved them. Do yourself a favor and make sure to have a good certified machinist level (at least .005/12") and check the level often. Check it with X and Y centered then at all four corners of travel...makes a big difference. I made parts for a metrology equipment manufacturer..laser tracker..probes, spindle analyzers and so on. Basically we made the equipment that checked the machines that were making the parts for! About every month or so we ran checks on the machines and they could tell right away if one was out of level. Its a PITA but its worth it if you want accuracy and less wear and tear on your machine.

Have fun man...I envy you ...I'm down to a hacksaw and ballpeen hammer now!!

 

[nicotime]

Yep that level should do it.

Hmmm...yeah thats not good...shims and vibrations never work well together. Sounds like youll be able to figure something out though. Good luck.