stop send me answears

john pcb

dear,

? I don't want to send me e-mails from answears

Re: PCB milling - getting started

Hi Jean-Claude.

I *like* your vacuum table.  Very ingenious.

What are you using for a vacuum source?

- Mark

Re: PCB milling - getting started

#36243

That vacuum table is a great idea!

Re: PCB milling - getting started

#36242

Hi Jean-Claude, yes, I'll send it this evening. you might need to change it to handle your format if it has any odd commands as some do.

Show quoted text

On Thu, May 9, 2019 at 9:40 AM casy_ch@... <casy_ch@...> wrote:

Hi Lee

Interesting description. Would you be willing to send me your hpgl to gcode translator. I use a cheap German pcb program which can only export HPGL, Excellon and Gerber files. I do not use Excellon and Gerber ones, not for me.

Regards
Jean-Claude

Am 08.05.2019 um 22:27 schrieb Lee Studley:

I didn't really pay much attention to actual depth( and the maths ;-) other than making sure the bit cuts through the copper fully.
My min trace width setting in the sw(altium) was 15mils.
I use an ancient copy of lpkf software ( from a machine I had years ago ) for the isolation. I wrote an hpgl to gcode translator to process a report that the sw generates.

I'm sure the sw you are using does similar paths.
The rate was about 3mm/sec so ~180mm/min

It could be your copper thickness: it looks like 2oz which might be harder to cut milling-wise(?) Are you in the usa? I can send you a sheet of what I'm using. I got it on ebay way back.

Re: PCB milling - getting started

#36241

Very good description Svetlo! thanks! -Lee

Re: PCB milling - getting started

#36240

开云体育

Hi Lee

Interesting description. Would you be willing to send me your hpgl to gcode translator. I use a cheap German pcb program which can only export HPGL, Excellon and Gerber files. I do not use Excellon and Gerber ones, not for me.

Regards
Jean-Claude

Am 08.05.2019 um 22:27 schrieb Lee Studley:

Show quoted text

I didn't really pay much attention to actual depth( and the maths ;-) other than making sure the bit cuts through the copper fully.
My min trace width setting in the sw(altium) was 15mils.
I use an ancient copy of lpkf software ( from a machine I had years ago ) for the isolation. I wrote an hpgl to gcode translator to process a report that the sw generates.

I'm sure the sw you are using does similar paths.
The rate was about 3mm/sec so ~180mm/min

It could be your copper thickness: it looks like 2oz which might be harder to cut milling-wise(?) Are you in the usa? I can send you a sheet of what I'm using. I got it on ebay way back.

Re: PCB milling - getting started

#36239

开云体育

Often I am milling 100 x 160mm PCBs as they are quite cheap here. To hold them I made a styrofoam vacuum plate and it is working fine. I have even used it for small aluminium parts with light Z-paths and so do not care if the mill is getting a bit lower into the foam. When the styrofoam vacuum plate is then to badly milled in, it is not a problem to make a new one in a short time. The paths are made with a ?2mm mill. The rubber band is also ?2mm.

Jean-Claude

Am 08.05.2019 um 09:03 schrieb elfwork@...:

Show quoted text

Hi,
I'm successfully milling PCBs on my cnc. The cnc is custom made but it is a small one with aluminum profiles frame and not very stiff. I haven't milled PCBs this big. My biggest is around 50mm x 50mm. I use smd components so I use two v bits one is 0.5 mm 30 deg and one 0.2 mm 15 deg (or maybe 20 deg). I use a double sided tape for holding the board. I use estlcam, but the software should not matter. I use flatcam for the gcode generation. So for 0.2mm bit I use 250 mm per minute and for the 0.5 mm one 350 mm per minute. The process is like this. I first make surface scan. Then mill with the 0.5mm at around 0.08mm - 0.1mm. This should remove the most copper (I make isolation milling 3-4 passes). And then mill with 0.2mm one at 0.1 mm depth (1-2 passes). I get the Z zero for the 0.2 mm around the lowest point. If the bending is more than 0.05 - 0.07 mm. I try to get it at higher point but never to have depth less than 0.05 mm. Also I try to make my traces thicker with the thinnest 20 mils if possible so bigger depth of cut do not make them too thin. Another thing I do is mill a waste board flat and hold it with just few bolts to the table and stick the PCB to that waste board. The speeds are probably quite slow. It takes quite some time to mill a board but I can leave it and do something else. I hope this helps. I'll share some photos in the evening.
Svetlo

Vakuumplatte_Raster10mm_90x140mm_01lowres.jpg

Vakuumplatte_Raster10mm_90x140mm_02lowres.jpg

Re: PCB milling - getting started

#36238

Hi Svetlo.

I haven't milled PCBs this big.I think the size may be part of my problems.  I have milled smaller
boards (about 30mm x 60mm and other similar sizes) without any problems.

The speeds are probably quite slow.I know what you mean.  The larger board I an milling takes a bit over an
hour to mill.  And that is without drilling :-)

- Mark

Re: PCB milling - getting started

#36237

Hi Lee.

The rate was about 3mm/sec so ~180mm/minI settled on the rates I used as it minimized the tear-out on the traces.

It could be your copper thickness: it looks like 2oz which might be
harder to cut milling-wise(?) Are you in the usa? I can send you a
sheet of what I'm using. I got it on ebay way back.I haven't actually measured the thickness.  The boards I'm using are
also from eBay :-)  I believe they are 1oz boards.  I should check.

Yes, I'm in the USA.  New Hampshire (northeast) to be exact. :-)

- Mark

Re: PCB milling - getting started

#36236

Hi,
I'm successfully milling PCBs on my cnc. The cnc is custom made but it is a small one with aluminum profiles frame and not very stiff. I haven't milled PCBs this big. My biggest is around 50mm x 50mm. I use smd components so I use two v bits one is 0.5 mm 30 deg and one 0.2 mm 15 deg (or maybe 20 deg). I use a double sided tape for holding the board. I use estlcam, but the software should not matter. I use flatcam for the gcode generation. So for 0.2mm bit I use 250 mm per minute and for the 0.5 mm one 350 mm per minute. The process is like this. I first make surface scan. Then mill with the 0.5mm at around 0.08mm - 0.1mm. This should remove the most copper (I make isolation milling 3-4 passes). And then mill with 0.2mm one at 0.1 mm depth (1-2 passes). I get the Z zero for the 0.2 mm around the lowest point. If the bending is more than 0.05 - 0.07 mm. I try to get it at higher point but never to have depth less than 0.05 mm. Also I try to make my traces thicker with the thinnest 20 mils if possible so bigger depth of cut do not make them too thin. Another thing I do is mill a waste board flat and hold it with just few bolts to the table and stick the PCB to that waste board. The speeds are probably quite slow. It takes quite some time to mill a board but I can leave it and do something else. I hope this helps. I'll share some photos in the evening.
Svetlo

Re: PCB milling - getting started

#36235

I didn't really pay much attention to actual depth( and the maths ;-) other than making sure the bit cuts through the copper fully.
My min trace width setting in the sw(altium) was 15mils.
I use an ancient copy of lpkf software ( from a machine I had years ago ) for the isolation. I wrote an hpgl to gcode translator to process a report that the sw generates.

I'm sure the sw you are using does similar paths.
The rate was about 3mm/sec so ~180mm/min

It could be your copper thickness: it looks like 2oz which might be harder to cut milling-wise(?) Are you in the usa? I can send you a sheet of what I'm using. I got it on ebay way back.

Re: PCB milling - getting started

#36234

Lee, your boards look good.

I'm using similar "V bits.  As far as I can tell there not any play
in the motor mounts or lead screws.  But I can't be certain without
actually bring out some of my machinist tools.

What sort of settings are you using?

The "skating" with the end mill, I used the following:
  Bit: 0.1mm end mill
  Spindle speed: about 8000 RPM
  Depth of cut: .2mm (0.0078")
  Feed: 30mm / min

I also had "skating" with a "V" bit using the following:
  Bit: 0.1mm 30 degree "V" bit
  Spindle speed: about 8000 RPM
  Depth of cut: .2mm (0.0078")
  Feed: 50mm / min

I was able to get a "good" PCB using the following:
  Bit: 0.1mm 30 degree "V" bit
  Spindle speed: about 8000 RPM
  Depth of cut: .4mm (0.0078")
  Feed: 50mm / min

Remembering my trigonometry, this last results in a groove about
0.2mm wide in the copper.  Fine for THT but probably marginal for
SMT.

I am using 0.062" single sided PCB stock.

All of these were using done using OpenCNCPilot with auto leveling.
It didn't matter whether I used a height map grid size of 5 or 10.

- Mark

Re: PCB milling - getting started

#36233

here's the proto w/ wider traces

Re: PCB milling - getting started

#36232

I had my min traces width set too low in this run, the later one was better, but I didn't have a pic handy.

Re: PCB milling - getting started

#36231

Yes, it does look like it was skating up or something loose in the mechanics. Should look alot nicer than that.??

I settled on using bits like these:?
Make sure there's no play in the slides and motor mounts, ballscrews. etc.
This picture had some too thin traces but shows fairly good results.

Re: PCB milling - getting started

#36230

To test the depth, I would add the board a trace to outline the board,
first for adjusting the depth.Great minds must think alike :-)

I ran a number of test patterns to test the depth of the cut as well as
minimal trace separation for a specific type of cutting / milling bit.

I've gotten reasonably good at editing the gcode files to make one off
runs.  As well as remembering my trigonometry for calculating the "V"
bit depth for a given surface width cut.

One thing I think is happening is related to the type of bit being used.

It appears the end mills I'm using, have a tendency to "skate" up.
Especially if any portion of the PCB is not absolutely backed.  The "V"
bits, I expect because of the taper to the 0.1mm tip, seem to be much
less likely to "skate" up.

- Mark

Re: PCB milling - getting started

#36229

Also what software are you using for creating the pcb then the isolation
paths?I'm creating the basic schematic & PCB layout with Kicad.  From there, I
use pcb2gcode to translate the Gerber files to gcode.  I'm using OpenCNCPilot
to do the auto leveling and drive the (Woodpecker) Grbl 1.1f board.

BTW, I was getting some really strange results until I placed ferrite chokes
on all of the stepper motors as well as the USB cable connecting the PC to
Woodpecker board.

- Mark

Re: PCB milling - getting started

#36228

Hi Lee.

Post some pictures of your attempts and the pcb mill so far.I've attached one example.  This was done with the 0.7mm end mill.

Are you shooting for smt fine pitch or general .1" stuff.At the moment, general THT and .1" stuff.  Nothing fancy.

- Mark

IMG_6030-mid.JPG

Re: Drill Press

#36227

开云体育

Hi James

In order to reduce the hair traces put a polaroid filter in front of the laser. By turning it left/right it does minimize the thickness of the lines. When I was using a laser cross beam for zeroeing that's what I was using. Polaroid foils are available, also a polaroid filter for cameras is good.

Jean-Claude, HB3YDH

Am 07.05.2019 um 15:23 schrieb wb8nbs:

Show quoted text

I have a Delta drill press that came with cross hair laser sights. It works after following a long alignment procedure but the beam is too fat to position anything smaller than 1/8". I think I have used it less than a half dozen times.

--
-- The only difference between men and boys, is the price of their toys.

Re: PCB milling - getting started

#36226

I do still use the mill to drill the through holes from a drill file.