Hot Hot (Yushengtech) SMT50 OpenPnP conversion

Upgrading the SMT50 hardware to work with OpenPnP

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I bought a used SMT pick and place machine from some sketchy dude on the internet. The host PC and Chinese OEM software were not included at the price. He said I could run it with a Smoothieboard and OpenPnP. So, I ordered a Smoothieboard and embarked on this adventure.

The SMT50 Machine

The guy that sold me the machine agreed to build a suitable shipping crate around it. Normally one would anchor an 80 lb machine to the bottom of the crate with bolts going through the crate frame and the base of the unit. Nope. It was just floating around in a sea of loose styrofoam blocks, which were pretty much disintegrated on arrival. Normally one would construct such a crate using 2x4s and 3" wood screws, or at least heavy duty long staples. Nope. He used 1x2, 1/4" OSB, and finishing nails. At least the feeders were wrapped in bubble pack.

The lid came off during shipping, and I suppose everything tumbled out on to the loading dock or wherever. FedEx repacked and screwed the lid back on with drywall screws. Damage noted on Fedex release : hole punched in 1/4" OSB by the hard rubber foot on the unit (WHAM!!!) and a broken cable drag chain. That wasn't so bad. However, I found more serious damage after unpacking the feeders. One of the feeders was beat up pretty bad. The side plate was bent, the shaft bearing was popped out, and the pull tape tension springs were bent. It was repairable with vise grips and a little muscle, and carefully tweaking the tension springs back into shape.

Slide Bearing Replacement

Much later, I discovered that one of the slide bearings was "sticking", presumably due to a damaged ball or race. I ordered a couple of new 16mm slide bearings from

Bearing removal began with a bench vise and a ridiculous amount of upper body force. It chattered as it gave way, but then I ran out of room on the vise, so I finished using a spark plug socket and 3 lb sledge hammer. I also used a propane torch to gently heat the block, but I'm not sure whether that actually helped or not. It was a VERY tight interference fit. There are also set screws on the block, but clearly they weren't necessary. I'm going to ream the hole slightly to ease installation.

Juki Nozzles

Ordered a set of 9 Juki nozzles (500-508) from RobotDigg, $133, or roughly $15 a piece. OEM nozzles are on the left in the pic.

Modify Head Assembly to accept Juki Changer

The lower part of the head assembly (below the yellow tubing in the picture) has a block containing a brass tube mounted in a pair of bearings, which extends the NEMA 8 stepper hollow shaft.

The bottom of the brass tube accepts the OEM nozzles, and incorporates an internal friction grip of some sort. I have ordered the Juki changer from:

for $49.99 + $13 shipping (wtf, ouch) and will modify or eliminate the bearing block to accomodate it. Original setup is 57mm overall from bottom of the stepper body to nozzle tip (best I can measure with a cheapo 6" digital caliper). The Juki setup will be about 54mm, per the drawing. So it's a good fit, and in fact I might actually gain a couple of mm on max component height.

Nozzle Rack

Existing OEM nozzle rack:

geniekobayashi 3d printed nozzle rack:

0603 is the smallest technology I plan to use, so I'll use the 503-505 nozzles to support 0603 through 2512, that leaves 506-508, so 6 positions should be sufficient. Hopefully that will fit across the front without cramping the board area.

Vision Subsystem - New Cameras

The existing cameras were both analog. The video signals were routed to a small board where relays connected one of the signals to the external RCA connector under PC control. This, in turn, fed into a no-name video capture dongle, then on to the host PC USB port. Geez, what a pile of crap.

ELP-USB100W04H-L36, $43

H.264, 720P, 30 fps, M12 (S-mount) lens

Logitech C270, $21


The PCB will be removed from the plastic enclosure, and a 3d printed adapter will allow use of an M12 (S-mount) lens.

Hizek Inspection Camera, $9.99

640x480, built-in LED illumination.

This could make a nice top camera, but would...

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  • Status Update for December 2018

    Darryl N12/22/2018 at 02:47 0 comments

    I've been MIA from HaD since early this year, so I wanted to give a status update to let people know that I have not abandoned this project.  

    As mentioned in a previous log(s), the big obstacle I encountered was adapting the pickup head to work with the Juki nozzle and the snazzy clicky nozzle adapter.  I was hoping to get my 6040 CNC machine working well enough to cut metal to build something. 

    The 6040 still isn't working, but the big exciting news (at least for me) is that I now have in-house machining capability! A mini-mill with 3 axis DRO, a 7" mini- lathe, a horizontal band saw for rough cutting metal stock, and all the required tooling.   

    Back in the late 90s/early 00s, I had access to a full-size mill and lathe, and was able to gain some experience making very simple parts using Al, ABS, and brass. So, I'm not a complete noob, but in the ensuing years, I've been doing mostly embedded software, so definitely need some time to refamiliarize. 

    Hopefully be able to make some progress on this project very soon now.  

    Meanwhile, please follow and comment!

    Planned upgrades: 

    • Redesign pickup head for dual Juki nozzles, eliminating the drag feed.  
    • Juki nozzle holder to allow machine to select and mount different nozzles with no interaction
    • "Smart" feeder system that detects the end of the components, throws a system fault, and allows hot-swapping the feeder and continuing the placement job.    
    • "Visual" feeder area using top camera to identify and pick cut tape and loose parts
    • New camera mounts and illumination
    • New control electronics (might not be a Smoothie)
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  • Status Update

    Darryl N01/19/2018 at 19:45 0 comments

    It's been quite a while since the last update. Sorry about that, but life intervened and I had to deal. I'm hoping to get back to work on this project within the next month or so, so stay tuned!

  • Status Update

    Darryl N07/11/2017 at 21:02 0 comments

    I think I have everything I need to move forward on this project....except time. I've been focused on my CNC project I need the CNC to make various parts and mods for the PnP, so need to finish it first. Hopefully wrap that up in a week or so.

    Regarding the mods to the PnP head assembly to accept the Juki nozzle changer, I have identified a couple of approaches that should work. One is easy, the other is a bit more involved, but arguably better.

    The simplest approach is to just remove the bottom section where the existing bearing/nozzle adapter were fitted. Rough cut on the bandsaw, and surface on the CNC.

    The other way is to open up the round hole in the bottom section so that the Juki changer can fit through it. Then (assuming there is enough material remaining) add a support bearing which should help minimize nozzle runout.

    Nozzle runout is a concern. The Juki changer secures to the stepper motor shaft with a single set screw, so any slop in the fit will move the nozzle off center. Plus, any angle between the motor shaft and Juki changer will cause the nozzle end to be off center. Ideally, it needs to be an interference fit, and the axial alignment needs to be very precise. Adding a support bearing somewhere along the length of the Juki changer would help minimize that.

  • Juki nozzle quick-change adapter

    Darryl N06/29/2017 at 00:11 0 comments

    Finally received the Juki nozzle quick change adapter! Next task is to work out the details of how to modify the PnP head to incorporate this, hopefully without losing any component height.

  • Hacking the Logitech C270

    Darryl N06/15/2017 at 04:53 0 comments

    Getting the board out of the housing was dirt simple - snap off the cosmetic face plate, remove 3 screws holding the front, remove 2 smaller screws holding the PCB, unplug the connector, desolder (or snip) the shield wire, PCB lifts out. Remove cable retaining clip, pass connector out through the cable entry hole, and reconnect cable to PCB.

    There was a blob of hot glue on the lens thread, knocked it off and the lens was adjustable. I was able to get 3" and 1" working distance into sharp focus. Larger working distances are possible.

    I printed the M12 lens adapter and mounted it to the camera. I found that the pink PLA leaks light and ruins the contrast, so I'm going to reprint using black ABS. Meanwhile, I wrapped it in electrical tape. Here's a link to the lens adapter on Thingiverse.

    The below pics were taken in PhotoBooth while holding the camera with my hand, so they are a little fuzzy from my hand movement and also not quite parallel to the object plane. With the right M12 lens, this will make a pretty decent down-looking camera.

    Logitech C270 at 3" working distance

    Logitech C270 at 1" working distance

  • Added SSD to Macbook Pro

    Darryl N06/14/2017 at 23:51 0 comments

    Macsales had OWC 60GB SSD on sale for $49.99 with free shipping, so I bit.

  • New power supplies

    Darryl N06/14/2017 at 19:09 0 comments

    This 48V-12V DC-DC converter handles 10A, pretty sweet, only $17. This will give me a massive regulated 12V supply off the machine's existing massive 48V switcher, which will power the Smoothieboard and any outboard stuff such as the vacuum handling.

    Smoothieboard also needs 5V, which by default it gets from USB but I prefer a standalone supply so for that I will be using a small DC-DC switcher that can do +5V at 2A from 12V.

  • New cameras

    Darryl N06/14/2017 at 18:54 0 comments

    The new cameras and lens kit arrived yesterday and I got a chance to evaluate. The ELP camera came with a 3.6mm lens. I replaced it with an 8mm from the lens kit. Works great, without any additional light other than room fluorescent. However, I did notice some distortion, so I will try applying lens correction in OpenPnP to see if that helps.

    Also had a play with the endoscope. Image quality was fuzzy and distorted. The built-in LEDs have no diffuser so they show up as a small circle of white dots on the PCB surface. Doesn't seem usable for precise SMT placement, but it's fine for basic inspection, so I'm going to throw it in my gadgets bin.

    Haven't yet looked at the Logitech C270, need to print the M12 lens adapter for it. As long as the image quality is good, and the right working distance can be set, I think it might be preferable because the PCB is thin and small enough to be mounted on the underside of the head assembly. Also hoping the existing LED ring can be remounted to line up with the lens.

    I configured OpenPnP for the endoscope as the top camera and the ELP as the bottom camera, using 640x480 and 5 fps. With "view all" cameras enabled, Activity Monitor showed around 37% CPU for the OpenPnP process, and each core was loaded to about 20%, so good balancing between cores. With the camera view disabled, OpenPnP was still burning up 25% CPU, I guess that's the best a bloated Java8 app can do, although it should be completely idle except for the UI events - empty job loaded and machine is not even started. However, since the Smoothieboard will handle all the real-time motion control, I think it will be sufficient for the UI and image processing pipeline.

  • New slide bearing installed

    Darryl N06/14/2017 at 17:57 0 comments

    Yesterday I headed over to my local maker space TinkerMill to ream the slide bearing block and press in the new bearing. They have a set of adjustable reamers and a 25 ton hydraulic press. I used a size "I" (capital letter i), and turned it by hand, to remove just enough material to true up the hole and open it up slightly.

    It was still a very tight fit, but the giant press handled it no problem. It chattered quite a bit on the way in, and I had to flip it over and back it out a bit to get the bearing centered in the block.

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