|Hardware: Laser T-962A «TVM802A» FilmScanner ePump Classic CAN|
Making a PCB
This is a little writeup of my experinces with the TVM802A pick-and-palce machine from China.
Pick-and-place is one part in the process of creating a working electronic circuit boards. Electronic circuits schematics are created on a PC, then converted into a PCB layout. PCBs are then fabricated by etching and printing.
To create a working board, solder paste is placed on the board using a stencil. Next, all components are picked from reels and placed on the PCB. Finally, the PCB is placed in an oven where the solder paste melts and connects the components to the pads on the board.
Connectors and some components are often soldered on manually. After that, the PCB is finished and should be ready for action.
The TVM802A is the cheapest PnP machine on the market that features dual cameras. The cameras are used to find the exact position of the PCB (downfacing camera on PnP head) and to align the components after they were picked (upfacing camera at the bottom left of the work area), so they are placed correctly.
I am currently planning 60 small PCBs that control the electromechanical display in a gas pump. Placing all the components on the board is tedious and error prone. When I saw the machine online, I decided to order one.
Ordering from China
Ordering from China is always - um - interesting. All prices are negotiable. Communications is via WhatsApp, SMS, or EMail, maybe online chat. You have to advance the money, and shipping costs are shocking.
Depending on your destination address, you need to add import tax and VAT. And even shipping via air freight can easily take four weeks. And when your crate finally arrives, customs may ask you silly questions before the machine is actually released (in Germany, add 10% tax to goods and freight., then add another 19% to the sum).
So I ordered June 22nd, 2015. I paid via PayPal (which took seconds vs. my bank, which takes weeks, but adds another 5% on you tab), and my sales contact promised to ship on June 23rd.
The machine was shipped immediatly (Payments via PayPal was confirmed within seconds, shipping happened the next day. arrivel in Germany three days later by DHL). Delivery was delayed by customs because DHL tried to reach me via some address they found on the internet. I am unsure if the sender missed adding my contact information, or if DHL got confused. 12 days wasted.
As far as I can tell, the shipment is complete. The crate was padded very well with foam. The machine is clean and sturdy. All vacuum nozzles are here, CD is here, wires are here. I am impressed. Only the power cord is Chinese, but should I really complain about a 2 Euro power cord?
The software is translated well enough. I saw one or two fields with a missing translation. But I was able to understand easily what is going on. The manuals are semi-automatic translations from Chinese and sometimes hard to decipher. Good enough. The machine comes with video clips on the CD that are helpful, once you have actually used the software.
Reading through the manual, it says that Win8 will not work, XP may or may not work, and Win7 is recommended. Well, I just bought an XP laptop becuase many drivers never made it to Win7 and up. It turns aout that Windows 8 works great. I havn't even tried Windows 7, and XP fails due to the lack of drivers (which is interesting as the cameras used are from Microsoft. Go figure).
The software is quite clear and pretty easy to follow. It's logical (as opposed to my laser cutter software), and it seems to be complete. The .CSV format is wonderfully simple. Adapting an Eagle ULP should be easy.
A Second Look
So today I was able to start and test the machine. The software works fine on Windows 8, but it will not work on XP SP3. The cameras in the machine are Microsoft Xbox 360 Live Vision Cameras which do not work properly with SP3. They are supposed to work with SP2, but I did not try that and downgrading is not an option.
On WIndows 8, both cameras are found without the need to install a driver. Both USB cables must be plugged in via USB 2 ports or better. The machine itself uses an Ethernet connection with a fixed IP. The software can be used as-is right from the CD. There is no installer. It's 99.9% English and relatively obvious to use.
Unfortunatley, the application windows are quite huge to make room for Chinese lettering and don't fit onto my laptop screen. I have to see if there is some way to scale things down. Running the TVM802A from a subnotebook is not possible. The controls would simply not be visible on a small screen. Running the TVM802A from a subnotebook is not possible. The controls would simply not be visible on a small screen.
The microcontroller in the machine seems to be limited. None of the controls work without the host software up and running. There is no SD Card slot and no standalone operation. All operations, all controls, all image processing is done on the host machine, requiring two USB and one Ethernet connection at all times. It's a design decision and it makes sense. Using the machine without vision would be a waste, and adding a vision system to the machine would have made it more expensive. I dedicated an older laptop to the machine and that should be just fine.
Testing all Functionality
In manual mode, all degrees of freedom can be tested. That would be X and Y axis motion, transport pin up/down, pick'n'place head 1 and 2 rotation, lift, vacuum, and and blow, and not to forget the protective film collector. Then there are the camers, the lighting, and the buttons. Everything works well.
The Host Software (V2.0)
I did manage to program the picking and placing of some parts. Calibrartion data is stored in the machine and is retrieved and used by the host software. Creating a pick'n'place program manually is quite painful and nothing you would do on a regualr base. The cameras have quite some lag. Make sure that the right camera is assigned to the right interface, or nothing will work as it should.
But I should not complain: nobody in their right mind will do this manually. Every PCB design software has a way to export pick'n'place data.
But enough for today. It's the weekend. I will continue Monday, shooting some pictures and maybe a video.
(c) 2012-15 Matthias Melcher