PCB CNC machine

Questions about the BatchPCB service

Moderators: phalanx, robacarp

rolmix
Posts: 6
Joined: Tue May 25, 2010 1:13 am

Re:

Post by rolmix » Tue Jun 08, 2010 12:09 pm

rf333 wrote:
funnynypd wrote:Do you have a few photos? A machine can make both PCB and stencil, that's very good, isn't it?
Here are some that I made lately:

phcnc:
Image
top:
Image
bottom:
Image
stencil:
Image
This board looks great!
I am curious what kind of material was used to produce the stencil and is it made on the CNC.
Is it plastic or metal?

User avatar
ohararp
Posts: 307
Joined: Sun May 01, 2005 8:43 pm
Location: Dayton, OH
Contact:

Re: PCB CNC machine

Post by ohararp » Thu Jun 10, 2010 9:01 am

Can I ask what bit you were using for your stainless stencil? Any other setup configuration for this that you could post would be appreciated!
Regards Ryan :-)
$25 SMT Kapton Stencils - http://www.ohararp.com/
US Distributor of PDS - http://www.ohararp.com/compilers.html

funnynypd
Posts: 162
Joined: Sat Apr 03, 2004 6:58 pm
Location: USA and Canada
Contact:

Re: PCB CNC machine

Post by funnynypd » Thu Jun 10, 2010 4:15 pm

I thought you could use the laser (CO2 type?) to cut the stainless steel. No sure how thin your laser beam can be focused.

rf333
Posts: 26
Joined: Tue Feb 24, 2009 10:20 am

Re: PCB CNC machine

Post by rf333 » Fri Jun 11, 2010 6:36 am

Yes, stencils are made on the mill.
The material is 7.5 mil nickel coated phosphorous bronze!
It has similar tensile strength as stainless steel and is great for machining. The tool is 8 mil stub end mill. Cutting speed is 7.5 inch/min @ 20 000 RPM.
I didn’t try any plastics yet, but I will some day :D

analogon
Posts: 130
Joined: Tue Mar 30, 2010 12:15 pm

Re: PCB CNC machine

Post by analogon » Fri Jun 11, 2010 8:19 am

How are the square corners made?

rf333
Posts: 26
Joined: Tue Feb 24, 2009 10:20 am

Re: PCB CNC machine

Post by rf333 » Wed Jun 16, 2010 5:19 am

analogon wrote:How are the square corners made?
All holes are actually rounded on the corners with a radius of 4 mil. They have been made with 8 mil stub end mill. The same type of tools that are used for copper rubout process.
Also there is additional “safety zone” needed for proper solder paste placement(it is programmable and in this case is 3 mil).
This is well visible on the screen shot. The green line is the actual tool path:
Attachments
stencil_cnc.png
stencil/cnc
stencil_cnc.png (151.43 KiB) Viewed 10719 times

funnynypd
Posts: 162
Joined: Sat Apr 03, 2004 6:58 pm
Location: USA and Canada
Contact:

Re: PCB CNC machine

Post by funnynypd » Thu Aug 19, 2010 2:53 pm

LED lighting are getting popular these days. Here is a photo how LEDs are mounted for PCB milling, very nice idea.
Image

rolmix
Posts: 6
Joined: Tue May 25, 2010 1:13 am

Re: PCB CNC machine

Post by rolmix » Sat Nov 27, 2010 9:03 am

Hello everyone
Our boss likes to get PCB mill (Accurate 360 or LPKF S62 – still not decided :) )

I have some questions

1) How is the process to match top and bottom layers ?
2) What is the max. drill diameter ( both machines have 1/8 collet) ?
3) What kind of maintenance is needed ?
4) Are they operating under the 64- bit W (7/vista) ?
5) What kind of Gerber files are needed are they the same from different CAD ?
6) Any practical impressions from PhCNC or CircuitCAM
7) How complicated boards we can run ?
8 ) What is the advantage of automatic tool change (seems that S62 has it) ?
9) What kind of tools are used ?

I have many more question… but enough for now.. :)
Regards!

User avatar
ohararp
Posts: 307
Joined: Sun May 01, 2005 8:43 pm
Location: Dayton, OH
Contact:

Re: PCB CNC machine

Post by ohararp » Sun Nov 28, 2010 8:27 am

Rolmix, here's my take on things now tha I have access to an S62 at our research labs.

1. S62 is pretty much useless without the fiducial recognition system.
You'll want this option to get your vias to line up properly.
2. Vacuum table is also a must have. Very inconsistent results without this.
3. Max drill size appears to be 3mm - http://www.lpkfusa.com/Store/pages/list ... /37&cid=37
4. Windows 7 and Windows Vista 64 bit aren't a problem
5-6. CircuitCam is pretty easy to use and uses standard gerbers
7. Depends on your tools (how fine are the routing tools) and via sizes

LPKF router has a nice enclosure that is really quiet. This is a nice feature. We disabled the "door is open" switches which I also highly recommend.

Overall the router is nice to have. Mainly from the ability to test out a chip and make an adapter board. I still prefer professional boards, but for prototyping its hard to beat. We cannot do through hole plating and must rely on the rivet option. This is a big limiting factor and I would not really consider this type of machine unless you were willing to really invest in a THP setup.

In summary, the system is good but with either option you really need to be ready to invest some serious money in the machine, options, thp, and tooling (those little drills/tools are expensive).
Regards Ryan :-)
$25 SMT Kapton Stencils - http://www.ohararp.com/
US Distributor of PDS - http://www.ohararp.com/compilers.html

rf333
Posts: 26
Joined: Tue Feb 24, 2009 10:20 am

Re: PCB CNC machine

Post by rf333 » Tue Nov 30, 2010 2:38 am

rolmix wrote:Hello everyone
Our boss likes to get PCB mill (Accurate 360 or LPKF S62 – still not decided :) )

I have some questions

1) How is the process to match top and bottom layers ?
2) What is the max. drill diameter ( both machines have 1/8 collet) ?
3) What kind of maintenance is needed ?
4) Are they operating under the 64- bit W (7/vista) ?
5) What kind of Gerber files are needed are they the same from different CAD ?
6) Any practical impressions from PhCNC or CircuitCAM
7) How complicated boards we can run ?
8 ) What is the advantage of automatic tool change (seems that S62 has it) ?
9) What kind of tools are used ?

I have many more question… but enough for now.. :)
Regards!
Hi
@ohararp already comment S62. I don’t have any hands on experience with S62, but have 19 months with Accurate A360
1.There are two ways to match top to bottom layers, using registration pins or using the camera (fiducial registration). I personally prefer the second one, it is easy, fast and more accurate.
2. A360 do not has any limitation in the diameter of the drilled holes. It simply uses a router bit for all holes larger than the bit. It is the same one that I am using for final cut-out. Software arranges this with just one mouse click.
3. Maintenance looks easy, according to Accurate, the linear bearings are lubricated for life and the screws need to be lubricated once in 3-4 years. I have contacted them on this matter. They offer small amount of the special lubricant used in the screws. I have changed already two spindle drive belts. Seems that they last less than Accurate pretends.
4. A360 have USB drivers for 32&64 bits Widows OS. Seems that the compatibility of S62 is based on USB to RS-232 outside converter, and the camera option is real USB. I just think that they have drivers for the camera, compatible with 64 bits OS.
5. I think both PhCNC and CircuitCAM don’t have problems with Gerber and drill files coming from any CAD system. A few months ago I have found a comparison tests, but can’t remember where.
6. My opinion is worthy only for PhCNC – easy, convenient and well build SW.
I had good impressions from CircuitCAM but they are dated more than two years ago, seems to me that it is more complicated and a bit harder to understand. The separate program to control the plotter (the name was Board Master I think) also makes the usage kind of more complicated.
In PhCNC you can go back and forth between CAM and CNC mode and correct things even after you start the machining (between the operations).
7. So far I did more than 30 boards (not only for me), many of them with LQFP packages and tight spacing.
8. I liked ATC too, but after my intensive questioning to the customer service of LPKF how the machine handles the difference between tool rings settings I have been told that the V type of tools should be set manually. That makes ATC not so impressive to me. On top of this the system was priced (at that time) at $22K.
Here are some useful sources for info: http://www.cityofxanthi.gr/ilias/Preise ... 011205.pdf
Second hand S62 are relatively hard to find and the prices are still too high.
9. Here is more useful info: http://ilab.usc.edu/wiki/index.php/CNC
I am buying my tools from PreciseBits http://www.precisebits.com/products/car ... ngrave.asp and Tink & Thinker: http://www.thinktink.com/stack/volumes/ ... chmill.htm
Looking at Accurate website seems that my A360 is replaced with new models. I am still very happy with it and don’t think that I need to change it.

rolmix
Posts: 6
Joined: Tue May 25, 2010 1:13 am

Re: PCB CNC machine

Post by rolmix » Sun Dec 05, 2010 9:01 am

Thanks “ohararp”, thanks “rf333”,
Your detailed comments are very helpful to me.
My boss is still not decided (waiting for one more offer), but we both agree that now is good time to buy.
Seems that everyone has good discounts before Christmas.
Thanks again and have Great Holydays.

marianmp
Posts: 6
Joined: Tue Mar 03, 2009 11:25 pm

Re: PCB CNC machine

Post by marianmp » Wed Apr 06, 2011 3:03 am

Hello everyone … I need help!

Have to make a board from material that I am not familiar with.
It looks like 3 layers, copper 0.03 to 0.05mm, insulation with similar thickness and aluminum close to 1mm. The sample is close to the size needed so I would like to avoid any error. Is there anyone that have some experience with this material using a PCB router. Tools, cutting speeds, feed rates. Every info will be helpful.
Thanks in advance.

rf333
Posts: 26
Joined: Tue Feb 24, 2009 10:20 am

Re: PCB CNC machine

Post by rf333 » Fri Apr 08, 2011 5:31 am

Hi @marianmp,
I can share some experience on this kind of material:
Insulation and rubout are practically the same as on standard substrates like FR-4.
I had some kind of worries about the drilling of the mounting holes and the routing of the board.
Apparently the structure of this kind of material is designed for easy machining.
Using the “peck” mode (available in the PhCNC Pro software) I drill the holes and rout the board successfully.
Here are some suggestions how to do it:
-mount the board using double sided tape
-insulate and rubout the board
-use 0.5mm increments in depth settings when drilling and routing
-set routing and drilling spindle speed to 40K RPM
-use 250mm/min plunge and horizontal feed for both operations
I do not know what type of the machine you are using but surely it can be done.

kamakaze
Posts: 1
Joined: Sun Aug 14, 2011 6:51 am

Re: PCB CNC machine

Post by kamakaze » Sun Aug 14, 2011 6:58 am

HI
Looks like A365 does a great job. Unfortunately it is definitely too expensive for my hobby purposes. I am trying to find a machine that is under 2000 euros.

Is this one totally useless or do you guys think that I can do quite simple PCB works with it?
http://cgi.ebay.com/4-AXIS-CNC-ROUTER-E ... 718wt_1396


Is it supposed to do two level boards too?

What are all the features/functionalities in A365 that are missing from the one I linked?

rf333
Posts: 26
Joined: Tue Feb 24, 2009 10:20 am

Re: PCB CNC machine

Post by rf333 » Tue Aug 16, 2011 5:00 am

Hi @ kamakaze,

Unfortunately many similar machines are on the market with claims that you can engrave circuit boards. This is completely not the truth. Current electronic components are getting smaller and smaller and the boards have to meet this trend.
If your goal is to prototype PCB’s you have to turn to the real manufacturers of this machines. As of my knowledge there are only 4 in the World.
They are lpkf, accuratecnc , t-tech and mits.
It is true, they are expensive, but how expensive is to get a machine for 1200 Euros that is good for noting related to PCB’s.
Here is why it will not work as described:
- Extremely low resolution, 0.04mm, in the worst case you have to have 0.1mm
- There is no depth control related to the surface of the material, this means that you can not use V shaped tools that are the main stream tolls for insulation of the traces and pads. This is actually the main problem that makes the dividing line between CNC’s for common usage to the ones designed for PCB prototyping.
- Very low spindle speed, the minimum that will do the job is 30 to 40000RPM
- Looking at the chuck the run-out is bigger than 4-5 mil (may be more). Any drill bit smaller than 0.5-0.8 mm will break immediately at this spindle speed and run-out.
- There is no software that converts the standard output of PCB CAD systems to real command code for this machine.
- I do not see any way to align top and bottom layers (this means you can do only single sided boards)
- Seems to me that there are many other issues that I did not go deep enough to find out but I definitely think that it is not good enough for PCB’s

I personally become a fan of Accurate CNC because my (now old model) 360 exceeded al of my expectations. This company is somehow different from the others. They do not hide technical information (as the rest do). On their web side you can get a lot of practical information.
As an example http://www.accuratecnc.com/mithsandtruths.html
If you take a look at the videos it will help you to decide how the process looks and how to approach it with the minimum spending (you will know what you need).
I also like the fact that they are the only company that listed the prices of the different models. Something that points to a kind of honesty.

Locked