Need clarificarion on LPKF Protomat S103

[azazen]

Hi there, does anybody know the working process of the vacuum table of LPKF Protomat S103? In the videos provided in the package CDs the surface of the vaccum table was damaged when holes were drilled. In the package there were no additional parts for the table, so is it a consumable material?
Another question on producing multilayer PCBs. How double-sided PCB is created? in the videos found in the package CDs the board is simply flipped over but how can you be sure in the accuracy of the board created?

 

[ArticCynda]

The vacuum table is indeed considered a consumable since it gets damaged by drills and contour routers, at least that is assuming your S103 works the same way as my S63. It's an extremely poor design, and the vacuum table is ultimately unnecessary since you can also simply tape your board down to a carton board substrate (as was the case for Protomat 95S/II or C100). The depth delimiter is controlled by a stepper motor, and you can simply configure the thickness of the carton board or MDF you're using in software.

Prototyping multilayer PCBs is hard because you'll need thinner FR4 copper clad board, prepreg laminate and a device to press them together under elevated temperature. You'll also need plating tanks for via's to connect the inner layers. In my experience, prototyping multi layer PCBs in house isn't worth the equipment and consumable you'll need for it. You can buy hundreds of 4 layer PCBs in China (wwww.pcbshopper.com is good start) for the cost of all the equipment you'll need to make your own multilayer boards.

Prototyping double sided boards is fairly easy, it's done in 2 runs: first drill alignment holes to be used as fiducials, then mill/etch top layer, flip the board and align using fiducials, and then mill/etch the bottom layer. This paper gives a good overview of the processes involved: https://www.academia.edu/7108733/Ex...cale_PCB_Manufacturing_Techniques_for_Fablabs

That said, the newer LPKF machines (including S63 and properly also S103) are absolutely overpriced crap. Buying a Protomat S63 was my worst investment ever. Machine broke down 2 time in the first half year due to hardware failures. The solder paste dispensing mechanism never worked properly. LPKF no longer offers support and forwards customers to its incompetent subcontractors. And then there is the CircuitPro software, which is littered with bugs and crashes as soon as you're trying to do something out of the ordinary.

I can highly recommend a Protomat 95S/II, mine is a second hand machine from 2001 and it still works like a charm. Automatic tool changer with 30 positions, very reliable, CircuitCAM is bug free and in BoardMaster I've only been able to identify a single bug in all these years.

I wouldn't recommend to buy new LPKF machines, they're a waste of money. And LPKF knows it, they refused to take my S63 back even after I was able to prove the hardware- and software failures. Worst customer service ever.

 

[azazen]

Thanks a lot. We already bought S103. hopefully, it will be working fine. I have a question on compressor. Both vacuum table and pneumatic depth limiter use compressed air. For the table the air is reversed in whereas for the limiter it is forwarded. How can a compressor supply them with air simultaneously?

 

[ArticCynda]

Are you sure your vacuum table is operated with compressed air? On my S63 the vacuum table is connected to a vacuum cleaner by means of 2 flexible tubes running from the table to the back of the machine. Compressed air is used by solder paste dispenser, and on some machines pneumatic valves and depth limiter (spindle head hovercraft).

An easy way to try this is to turn on the vacuum cleaner manually. You should feel the vacuum table **** the PCB to the table if everything is properly connected. As for the compressed air, make sure you use dry air with a pressure of max. 6 bar.

 

[azazen]

No, I wasn't sure about that. I'd read from the manuals that vacuum table requires compressed air for proper operation; that's why I believed so. Now I am clear on that. Tnx)

 

[ArticCynda]

I don't know much about compressed air, and I assume it's possible to create a sucking effect using the Bernouilli effect, but I think it's much easier to use a little fan or vacuum cleaner instead for low under pressure and high throughput.

Good luck setting up your machine, if you have any questions feel free to ask!