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Forum Index : PCB Manufacturing : Using a CNC mill to create PCBs
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TassyJim Guru  Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
I am thinking about buying a CNC for general work and making PCBs. The shortlist is a 3040 or 6040 cheap Chinese machine. The shortlist might get shorter depending on the success of an auction next week. I have DEX to create gerbers. I assume FlatCAM for converting into G-code or DEX has a CNC output which hopefully does the job. and Mach3 to drive the CNC. I have an old XP box with a parallel port so that side is covered. I currently use veroboard for prototypes (and rarely get beyond prototypes). If I get this working, I will be making good use of Mick's hard work with DEX. Jim VK7JH MMedit MMBasic Help |
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plover Guru Joined: 18/04/2013 Location: AustraliaPosts: 302 |
Jim This process of using isolation technique I first employed by hand in the 1970th the problem was prototype turn around time. Todays SMC use it is too hard I believe. This lead me to look for proper small CNC doing this job but it was out of the question cost wise. The breakthrough in this area in my opinion was the Elektor version created in cooperation with a manufacturer who downscaled one of their models and offered a kit for Elektor members. Both Elektor and the company completely underestimated the interest and there was long queue to lay your hand on one. When they started to produce results for owners it soon became clear that to get really good results improvement were needed. One in particular I remember was the router, I think you need at least 30,000 rpm and preferably 100,000 rpm but the cost then start creeping up dramatically. You should however be able make surface mount lands with confidence. Further you will have your board within hours and probably functional. I don't know what the state is of those machines made in Europe, most likely they have long ago been copied by the chinese factories. Maybe the ones you are looking at are based on the Elektor unit. Personally I dropped out of that race and went 'photographic' Risdon board etc using high quality Inkjet printers to make the negative positive as required. Actually more I encourage a friend to go that way and now and then got small boards made at the same time. After he closed shop I har already dropped out as I got interested in Linux and could not find the time for both. Now I am getting interested because of DEX mainly to make schematics of a few projects I have in mind. Another story. Here in the Backshed I discovered that quality boards can now be made in China at very reasonable price it will be hard to justify for me doing my own boards as I probably may need quite a few identical boards at that. 1.. Look out for the whole Z-axis operation and router speed 2.. Swarf removal from the operation via vacuum 3.. To set the cutting depth, have a pressure foot to ensure even depth. 
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
Making progress with the selection. I had a really good day at the auction yesterday so the budget has increased. http://www.examiner.com.au/story/3970724/rare-porsche-auctioned-for-huge-price/?cs=5312 I usually only want a single board and tend to stick to through hole components so the small size restrictions shouldn't be an issue. I will probably go with a 6040 with the 4th axis for wood turning. There is now a version with USB instead of parallel port so that makes finding a PC to drive it with easier. The 6040 has a good spindle speed and plenty of power. (OK that's if you believe the specs) If I don't find any Australian stock, I have a 4-5 week wait. Jim VK7JH MMedit MMBasic Help |
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MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
I would not be so sure about using a USB version. Parallel version exposes the machine more so you could use it for other purposes as well. Maybe even for solder dispensing or pick and place with open pnp. Microblocks. Build with logic. |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
That is a good point. I can always purchase an external SmoothStepper motion controller if I do need USB (or ethernet) Jim VK7JH MMedit MMBasic Help |
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| MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
If you are up to it you can go for a kit. It will give you deep knowledge on how eveything works and that is invaluable for repairs and modifications. The chinese parts are ok but often lack in quality. Maybe also include a kit or two in your shortlist to consider? Often you get more quality for the same price although only interesting if time allows it and you have the will to do it. I build my Ultimaker 3D printer as a kit, and that helped me so much to keep it running and tuned. That would have been a lot more difficutl when i would have bought an assembled one. But then again if i buy something assembled the first thing i do is disassemble it.  
Microblocks. Build with logic. |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Wow, congratulations Jim, Launceston must have fairly rocked - it's amazing how enthusiastic an enthusiast can be! Greg |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
It certainly gave a boost to the tourism sector. I was amazed at the number of bidders willing to go over 50k Bidding slowed down by 70k and the last few k was like pulling teeth. The journalist made at least one error - I didn't have a wife on the trip in 1981. Jim Still waiting for the loot to arrive in my bank account... VK7JH MMedit MMBasic Help |
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| MikeO Senior Member  Joined: 11/09/2011 Location: AustraliaPosts: 275 |
Jim, I missed your post on this as I have a CNC machine and regularly cut boards by isolation milling. I have a Carving unit basically a 6040 unit with 800 VFD water cooled motor. It seems now that carving have changed their name. I went for this model as it had more substantial drive rails at 20mm. I purchased a parallel drive unit only because I intended to rebuild it to my own specs and drive card which is USB from a company called Planet-CNC. I have had very good results with the software and can recommend it. I use an XP box. It has taken me some time to learn some techniques but i am now very happy with the results I am getting. Cheers Mike Codenquilts |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
Thanks Mike, I ordered the 6040 with parallel port and TOLL transport have it in their hands. Should arrive next week. I have the XP box ready and just need to do some work on the table it will sit on. I had some minor surgery last week and need to get over that before doing any heavy lifting. When a surgeon says "there might be some discomfort", you know they are really a sadistic b... Jim VK7JH MMedit MMBasic Help |
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| MikeO Senior Member Joined: 11/09/2011 Location: AustraliaPosts: 275 |
Hope you are fighting fit soon. Did you get the 4th axis? If so I would be interested to see how you go with it, I have been tempted to get one several times but been put of by things I have read. Mike Codenquilts |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
Yes, I only had one chance to spend up and while I do have a lathe, the 4th axis was too tempting to miss. It will be a while before I do anything exciting with the 4th axis. I am going to start with some wood carving to impress the BOSS and then some bezels for the growing collection of LCD displays. I also need to track down a supply of treffolyte for some durable labels. All much more exciting than going to vote. Jim VK7JH MMedit MMBasic Help |
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| MikeO Senior Member Joined: 11/09/2011 Location: AustraliaPosts: 275 |
Look forward to that info. I think you may be quite CAD experienced but I use CamBam for drawing up my milling operations, bezels and enclosures like my latest project , I also did the plastic fabrications for the motor and bearings mounts on the mill. Here is a couple of shots of isolation milling , you will note I haven't made the move to SMDs yet! 
Cheers Mike Codenquilts |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
@Mike CamBam looks interesting. I will certainly give it a try. Your boards look good. I will stick to using commercial carrier boards to get the small surface-mount ICs up to through-hole size, just like I do now for veroboard. What spindle speed and travel rates do you use for doing the boards? I have some 30 degree 0.2mm engraving cutters which seem to be right for the job. Jim VK7JH MMedit MMBasic Help |
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| MikeO Senior Member Joined: 11/09/2011 Location: AustraliaPosts: 275 |
@Jim, Yes those 30' 0.2mm V bits will be good, I use those. I traverse at around 1000mm/min and spindle speed 12000rpm. I am getting better than 0.075 - 0.1mm cutting depths now , Planet software has a feature called Warp that allows you to map out a grid on your copper (by touch sensing) of surface depths which can then be applied to your gerber when you import it. Its cool to watch it dynamically adjusting the cutting depth as it mills the board. Mike Codenquilts |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Tassy, Been a member here for quite a while and have built a CNC Router Milling machine a few years back. I am pretty familiar with Cambam and Mach3 and use it to make PCBs but i do run into problems with bridging caused buy the material ( copper & Fiberglass) Left into the cuts and plays havoc when finished. My spindle is a 1 kW VFD Water Cooled and runs at 24000Rpm. I have been able to transfer some circuits to CB and G Code using a PDF to Cad program as a trial but it works with the limits they put on a trial so but I am sure there are better ways that dont cost $500+ just to do a few boards now and then. Then there seems to be the online places that will do it at a cost, has anyone used these places with success and can recommend. It would be nice to be able to seamlessly convert from gerber, .pcb or express files to DXF. So I suppose my question is and just throwing it out there to the Electronics and Maximite etc side of the forum. I see mike uses Cambam to do pcb's and how well does that go, and have you found any settings specifically that are used so hopfully he sees the question as well ? PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
I think I was lucky with the machine I ended up with. None of the drama that I have since read about. I have yet to cut a board but I am getting close. I use DEX for the PCB design and the CNC files it produces look like they will do the job. This will save one step in the process. I am starting with single sided boards and I wrote a program to flip the DEX drill files so I can do that step from the bottom without the need to turn the board over. One less step where disaster can prevail. I like CamBam for quick bezels etc and for now I am still on the trial version. I leave it running all the time so it will take a while for the 40 starts in demo mode to finish. By then I will know if it is worthwhile purchasing. Trying to learn DEX, CamBam and Mach3 all at the same time is interesting. I have limit switches fitted to the mill now so that makes me a bit happier. I also have a heater in the shed now so that makes me a lot happier 
This is a nest of bezels for 7", 4.3" and 2.4" produced on a bit of scrap acrylic sheet. Jim VK7JH MMedit MMBasic Help |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6111 |
My first (I don't count the first first attempt) PCB 
Still a lot to learn. I used DEX to do the layout. I am having a problem with DEX but I am confident that Iliya will have a solution soon. (A strange bug and I am glad that it's not me that has to fix it) I wrote a program to flip the drill file so that I can do all the engraving and drilling from the bottom side without having to re-position the board. AutoLeveller was used to probe the board and compensate for the lack of flatness. TurboCad followed by CamBam did the board extremities. There are a couple of areas on the board that needed manual cleanup but, for a first, I am happy. 
Jim VK7JH MMedit MMBasic Help |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1352 |
Hi Jim, I havent played with my cnc for a few years and I did have a go at milling pcb's only find my old computer hung when the board was nearly finished which put me off until I could get a better computer. Now I used Sprint Layout as the software to design the pcb and a single button click will make it isolation. To convert the gerber and drill files to G-code I used K-cam which I found did an execllent job of converting and with the sim feature one can see on screen the g-code output before milling. Regards Bryan |
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