SMT Troubleshooting: Common SIPLACE Errors

When a SIPLACE pick & place machine starts generating errors, the temptation is to act on the symptom: change the nozzle, reload the feeder, restart the machine. Sometimes it works, but often the problem comes back because the real cause is elsewhere. Effective troubleshooting on SMT lines is first of all a method: isolate the phenomenon, read the data the machine already provides, distinguish cause from effect. In this guide we look at the most common SIPLACE errors and how to tackle them, from pickup errors to vision errors, and at when remote support is enough and when on-site is needed. The expertise behind these notes is that of someone who has worked on ASMPT/SIPLACE lines since 2021 (credentials).

1. The step-by-step diagnostic method

Before touching the machine, it is always worth following an orderly sequence:

1. Define the phenomenon. Is the error on a specific component, on one head, on one feeder, on one position on the PCB? Is it systematic or random?
2. Read the logs. SIPLACE machines record errors, pickup statistics and placement data per nozzle, head and feeder. The numbers tell you where to focus.
3. Isolate the variable. Move the component to another feeder, try another nozzle, change head: if the error follows the component it is a shape/data problem, if it follows the hardware it is mechanical.
4. Check one thing at a time. Changing several parameters together makes it impossible to understand what fixed it.
5. Confirm with the data. After the intervention, check that the error statistics have actually come down, not just that the machine "seems" to be running.

2. Pickup error: causes and diagnosis

The pickup error is the most frequent error. The machine cannot pick the component up, or loses it immediately afterwards. The typical causes:

• Nozzle: worn tip, dirty with flux or blocked, insufficient vacuum. It is the first thing to check.
• Feeder: incorrect advance, tape not indexed, component not in the pick position, worn cover.
• Pick height: incorrect setting in the shape or in the job, which leads the nozzle not to touch the component correctly.
• Component: actual dimensions different from the data, non-conforming tape, deformed components.

Correct diagnosis starts from the statistics: if the pickup error is concentrated on one feeder, the problem is that feeder; if it is spread across all the feeders but on one head, the problem is the head or its vacuum; if it follows a single component everywhere, it is a shape or tape problem. For structural feeder management we refer you to the guide on SIPLACE SMT line maintenance.

3. Recognition and vision errors

Vision errors show up as components discarded after picking ("recognition error", component not recognised or rejected). The vision system compares the image of the component with the stored shape: if it does not match, it discards it. The causes:

• Wrong or imprecise shape: incorrect body dimensions, pads, polarity or number of leads. It is the most common cause of false rejects.
• Lighting: degraded LEDs, lighting parameters not suited to the component (reflective, dark, transparent).
• Dirty optics: camera with dust or residue, blurred image.
• Camera calibration not up to date.

When false rejects are concentrated on one type of component, the shape is almost always responsible: it is worth reviewing it carefully, as we explain in the guide on SIPLACE Pro programming and component shapes. When the error is generalised, on the other hand, you look at the vision hardware.

4. Feeder problems

Besides the pickup error, feeders generate specific errors: failure to advance, indexing error, end of tape not detected, communication errors on electronic feeders. Typical diagnosis:

• Check whether the error is on the slot or on the feeder: by moving the feeder to another slot you understand straight away whether the problem travels with it or stays on the machine.
• Check the sensors, the mechanical advance and the tape tension.
• On electronic feeders, check the contacts and the communication with the machine.

An off-line feeder calibration station reduces these stoppages: the problematic feeder is found at the bench instead of in production.

5. Placement accuracy out of tolerance

When components are placed but off centre (systematic offset, rotation, fiducial misalignment), the problem is one of accuracy. Possible causes: system calibration to be redone, head-to-camera offset drifted, mechanical play in the axes, PCB references (fiducials) read badly, incorrect job references. The key distinction is between a systematic error (the same offset on all components → calibration or reference) and a random error (scatter → mechanical play, vibration, pick problem). A drop in CPK on fine components (0201, QFN, BGA) is the first sign that accuracy is degrading, and it has to be dealt with before it generates soldering defects.

6. When remote support is enough and when on-site is needed

Many SIPLACE problems are solved remotely: reading the logs and the statistics, guided support for the operator and, together with your team, correcting shapes and job parameters and adjusting pick height and lighting. It is quick and avoids the travel. On-site work is needed instead when the problem is mechanical (system calibrations, head overhaul, play in the axes, hardware replacements) or when the remote diagnosis identifies a cause that requires hands on the machine.

ElectrONIK Lab offers both modes within its SMT support services: remote diagnosis is tried first, starting from the machine's bug reports, and we come on site when physical work is needed or remote work can go no further. The objective is to reduce downtime and bring the line back up to speed, as explored in the guide on how to reduce machine downtime on an SMT line.

Frequently Asked Questions