This is log of the current work we’re doing at NSL http://032.la
Rather than hand build all the badges for our socal security conference layerOne again, http://www.layerone.org/ we’ve gone to a pick and place machine.
Gleep found us a Juki(Zevatech) Placemat 360 (that seems to have been upgraded to a 460 ) pick and place machine. It was sold as ‘working’, the sellers definition was, if I’m completely honest a stretch (outright lie).
This is actually our second pick and place machine, we don’t mention the other one
We’re also interested in acquiring a Zevatech/Juki 460 if you have one for a decent price.
Basically he demo’d everything that didn’t need a compressor, that all worked. Of course everything that needed a compressor as we found out later, didn’t work! Still $1,200 isn’t bad.
I used my supersilent 20a as a temporary compressor, it only has a small < 1 gallon tank, but its actually quiet, we used the 8 gallon compressor at null space which is deafening, so i found a 3 gallon temporary one at harbour freight for cheap in their recent sale. its too small though, so we’ll need shop air at some point. The supersilent was causing the pickup head to fail to work after a few passes, so this caused as a few false starts, the machine needs a solid air supply to function , even in testing.
The existing filter and pressure regulator was a mess, so off to home depot to come back with the best we could find there, which isn’t that great.
This is the old one, remember sold as working. No filter, and all these bits were just lying around inside it.
The machine itself is based on the PC-8801 Z80 4mhz CP/M which I recognised straight away as my old job had me doing game conversions in Japan for the PC-9801.
The whole machine works pretty much on the principal of that if the CNC software said do this, do that, that it executed perfectly. Only limit, head, home and the tool changer have checks.
We fired it up , Krs and Gleep got it picking and placing a few resistors (though they somehow managed to get the tape removal part completely wrong and it was throwing resistors all over the place. Then mmca got it placing QFP parts correctly. The lamp spot system was off, the 90′o rotation was off, the tubes were old and cracking. Compressor filter was non existent and rusted out. We’ve also discovered the whole thing is covered in parts from the previous owners, we’ve scored a few 100 0805s and some IC’s.
The reed sensor was the first thing we found that was broken, a quick trip to eBay and a few days later we had replacements. Luckily Juki is in heavy use, and they use a lot of off the shelf components. Apparently the later 5xx machines do switch to a proprietary drive system.
The reed switch detects if the head is up or down. Its one of the few sensors in this machine. The bend has caused the wiring to break down internally over the years. so the machine gets confused about being up or down, and the software doesn’t cope well with that, it basically needs a full reset afterwards.
The new sensors , $9 from eBay.
I also bought a CPLD based floppy emulator from Poland, it hasn’t arrived yet and we’ll probably be done with the new system before it gets here, and we’ve discovered the speed stays the same but floppy drives won’t last so the SD is still a good replacement.
Placing QFPS (AT90CAN128)
Fashioned a quick tray for the IC placements. We use these great little boxes, also from eBay, for holding SMD components, they double up as handy platforms too.
The feeder is controlled by the head, it moves over the spring loaded pin and pushes it down, this releases air and the notched wheel on the right moves the component reel tape one step, at the same time the protective covering tape is peeled away, allowing the machine to come back and pick the part up. This time, they’re correctly threaded, previously the protective tape was wrapped around the pin in the middle.
Side view of feeders, you can see the reel of components on the left, and the pneumatics underneath. Its important to choose a pick and place with a widely available range of cheap feeders, all too often people buy a cheap pick and place then find out it has none, and it’ll cost $1000’s to get them, if at all.
Feeder with pneumatic assembly
The expansion board
This is the board inside the machine, it is a couple of 8255s which are the defacto standard for PC parallel IO, almost every PC has had one or more of these, they’ve since moved into the ASIC’s but the principle is the same. It memory maps each of the input/outputs of the machine so that host PC can see them. I pulled off the floppy image, copied the files to my PC and reverse engineered the controller code with IDA.
I found an IMG of the floppy online, this was MFM encoded . So i converted that to a raw binary file, and then used cpmtools to copy the files from it. I was hoping to find some of the saved files so we could reverse the format and write a quick tool to do the placement. Once the files were copied off i tried a few of the different PC-8801 emulators, M88 etc, but had no joy in getting it running. So finally I just pulled apart the CP/M COM files in IDA and see what we could find.
The teaching process is tedious, so reversing the format would have been worthwhile.
This board takes the IO from the PC, buffers 74LS240 it and uses power darlingtons FT5723M to switch the 24V signals for the pneumatics. As well as read the various sensors and the + / – for the motors. The motors and stepper drivers are off the shelf, but very nice, we even have newer versions of the motors and controllers at NSL.I’ve removed the bottom connector to make it easier to take pictures.
The grey cable that has been added later is the automatic tool changer, this is soldered directly in the spare connections , 5V and 24V VDC. The 5V powers the small adapter board in the ATC and the 24V is for the pneumatic switches.
The remaining signals are multiplexed IO that are demuxed by a 74Ls138 on the ATC board, which deviates from the way the rest of the board works as the rest are all controlled by the darlingtons directly.
Each function of the machine is basically <control> – <buffer> — <pc> – <memory map>
So if you want the head to go down, you flip a bit in the PC’s memory. Its all digital IO, nothing fancy at all. The only extra part is the 5V TTL to 24VDC for the pneumatic switches.
Stepper drivers and power supplies.
The stepper drivers are on the bottom, the other one is to the right under the tray. the two power supplies are just visible at the top right, one is a 5V the other a 24V. The power filter is in the lower left.
Stepper motor driver
Since the machine was in bad need of service, we stripped it down, here the XY belts are visible. The top side has the the driver motor and the bottom side gets its power from a rod under the bed on the right side, so both belts are moved in unison. The ATC is in the top right and the frame in the middle is what is left of the PCB holder.
Tearing it down.
mmca stripped the head down. here it is removed from the gantry. mainly because there is a piece of string visible , and we can’t figure out what its for.
Shims, we don’t think these are factory shims.
The strange piece of string inside the head… What could it be for?
Bottom view of the tool pickup and the 90’o rotation.
These 4 arms are moved towards the part and clamp it gently, this straightens the part for placement, it can also rotate the part by 90’o ( which sucks for us because i always like to put parts at 45’o)
laser, focused lamp (this machine continues to surprise us ) which is used to position the head in teaching mode.
We’re removing the lamp and replacing it with machine vision, so some measurements are taken.
The hoses are removed and marked with a letter , the corresponding connector is also marked with the same letter.
This is how the previous owners repaired the 90’o rotation arms….. so that explains the string. this was removed and repaired correctly. The 90’o does just that, it rotates a part by 90’o that’s all this machine can do, so we’re going to change that to it can do arbitrary rotations.
This hose had cracked, a few others did too. I found a few temporary replacements at the auto parts store 4mm ID, 8mm OD fuel priming line. The plan is to replace all the hose.
Stripped machine screw in the head. Replace from grainger, M3x8mm 0.4mm thread 5.5mm head size.
And some missing set screws
Spent some time measuring all the screws and what not. The machine is old enough that it came from proper manuals with circuit diagrams.
This board is a dumb board, it just marshals the I/O and does the switching of the 24VDC with darlington’s.
Here we’re removing and verifying the connector sizes and function (the manual had some errors) so its good to do that. It also gives us good insight into what’s going on.
Checking how the machine works with my trusty fluke.
I threw together the connector layout in eagle and printed it out to verify it, early revision.
Measure the hole size and distance. Our board is exactly the same size so its a drop in replacement, we’ll just lose the two larger connectors and change it to USB.
Here we were figuring out how the ATC worked, at first it was though to drive it directly , but there weren’t enough wires. So its 24V, 5V and control signals, the small interface board at the front is a 74LS138 decoder/demultiplexer with a few buffers and more darlington drivers , it switches the 24V on and off based on the 4 control signals coming in.
Automatic Tool Changer
The tool wanted is lifted up when the machine wants to change it, on the right are the pneumatic switches that are controlled by a 24V signal.
We’re using Power MOSFETs to control the 24V instead, a 6 pin ROHM US6K1DKR in a TUMT6 package ( time to create a new device in eagle again !) I ordered 100 from Digikey yesterday and should have the board layout finished today. Then we can mill out a test PCB and see how it works. (parts arrived a few minutes ago!)
You might be amazed, I was , about just how simple this machine is, you could run the whole thing from a set of on/off switches, albeit very slowly. But that is great for us though as it makes it very easy to replace the PC software.
The next big thing is going to be testing the new power MOSFET and building the new PCB. The chips
will be here today have arrived.
So new eagle package
Cut out a few to test.
Apparently I goofed on the measurements, I did change it around a tad after the first revision. Teeny part.
Soldered it anyway
So the next step is adding cameras etc.
mmca explaining the new part to be cnc’d out for the camera
mockup of the mount
The head has to be recalibrated so the bottom of the tool is 62.5mm from the table, with a .1mm accuracy, so we as usual went overboard and used grade B gauge blocks.
69.5mm to .00005 inches accurate.
Gauge blocks are fascinating, they stick together like magnets if you put them together by making surer there is no air between them, but if you just stick them together they won’t. Super flat. these aren’t grade a or better, but they’re nice. mmca has the coolest stuff.
Starting to rebuild it
Machine vision tests
This is work in progress, testing RoboRealm/OpenCV and teaching it components, it works well!
Using a panda board a HP HD Webcam for testing the vision.
Playing around with layouts for a quick test tool. two grey areas are for the cameras.
Well that is it so far, my Motorola Atrix decided that the fingerprint reader would become burning hot to the touch. So I pulled it apart and removed it, but somehow managed to make it do a full hard reset (or a docwho76 as we call it ) and it deleted a bunch of my pictures. google+ had failed to sync them. But we’ll keep documenting the project,