7 posts tagged with "openpnp"

A desktop pick and place machine at $1,499 buys a machine that is already built. The Vertex 4 arrives assembled, wired and calibrated, with a dual JUKI-compatible head, top and bottom vision, a 500 × 400 mm work area, 50 feeder slots and one set of manual tape feeders in the box. Build time runs 5 to 10 days.

That covers the machine and says nothing about your board. On my own bench the questions that have actually stopped an order are part height, part weight, lead pitch and panel size, and none of them appear on a price comparison page.

The first sign is rarely a light. It is a 0603 landing a millimetre behind its pads on the first board of a batch, and the same millimetre on every board after it. By the time anything goes red you have scrapped a few boards.

On a Vertex 4 I have run short feeds, double feeds and a feeder that dropped off the RS-485 bus mid-job, plus one that was fine when I pulled it out and put it back on the shelf. The order below costs a pen and a pair of calipers before it costs a spare feeder.

The first sign was a 0402 that came back from the bottom camera sitting at an angle.

I was halfway through a 20-board batch of a small sensor board: nine 0402 decoupling caps, a dozen 0603s, two SOIC-8s. The machine is a Vertex 4, running OpenPnP. It ships with a 503 and a 505, and the 503 went into N1 for the small end of the BOM, which is the reasonable reading of those two nozzles if you have not thought about it much. I had not thought about it much.

The bottom camera is arguably the most important vision system on your desktop pick-and-place. It's what verifies that the component is correctly oriented on the nozzle before placement. Get the exposure wrong, and you're either blind to misaligned parts or drowning in false detections.

Most OpenPnP guides tell you to "adjust exposure until it looks right." That's not helpful. Here's what's actually happening and how to calibrate it properly.

Photon feeders use UUIDs (Universally Unique Identifiers) to communicate with OpenPnP. This is generally reliable, but it creates a specific class of problems when feeders share IDs, get reassigned, or conflict with each other. If you've ever seen OpenPnP detect the wrong feeder or fail to recognize a feeder that's physically connected, UUID conflicts are the likely culprit.

Here's what's happening under the hood and how to fix it.

Your nozzle has no vacuum and you can't pick anything up. Before you start unwiring the solenoid, check the actuator command — on the PikkoBot Vertex 4 that's the cause far more often than a hardware fault, and it's a one-field change.

Fiducial detection is the backbone of accurate placement. When OpenPnP can't find your board's fiducials, the entire assembly process stops. Before you blame the software, work through these five fixes in order—they resolve the vast majority of detection failures.