Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Component Overturn

#24439

Component Overturn | 7 May, 2003

I am from the Quality Dept. There is this SMT defect that were root cause to defective feeder that lead to component overturn during feeder indexing. I ask for corrective action from the SMT engineer but apparently there is not much he can do except change the feeder. According to him is this a common problem and there is no way to detect such symptom.

reply »

#24440

Component Overturn | 7 May, 2003

Bollocks!!!!

We are unfamiliar with the term overturn, but it can not be that uncommon. Our intial inclination is to barrel into this SMT Engineer's nap-zone and blast him, but it might not be a politic approach. So, maybe we'll temper the tack we take on this.

Since you are the quality-person, tell us about: * Calibration procedure for this feeder class. * Calibration schedule for this feeder class. * Performance indicators that highlight the need for feeder maintenance. * Methods of tracking of these indicators by your operators. * Go / No Go levels for these indicators that require your operators to enter a feeder into maintenance.

reply »

Kris

#24443

Component Overturn | 8 May, 2003

Hi,

Would it be likely that the component carrier you re using is too large for the component with the result that the vibration during feeder indexing is overturning the component ?

comments

reply »

#24444

Component Overturn | 8 May, 2003

I like to find out more about your feeder manufacturer. Known problems:

If the cover tape peel back is located in the pick up window, the tape may lift the component out of the pocket and when the component falls back it could be inverted.

The component is rejected by the acceleration of the tape. Upon deceleration the component slides back into the pocket but inverted.

The entire advancing mechanic creates vibration. Enough to shake the component out of the pocket and possibly flip the component.

The support plate underneath the tape is not correctly sized. When the tape pocket deforms in the pick window, the component is rejected out of the pocket.

The reason Kris mentioned.

None of these root causes could be eliminated with maintenance. However, most feeders have a shutter lid covering the component while the tape advances. If the lid is bend and give the component room enough to flip, than this is indeed a maintenance issue.

P.S. I forgot to add that the shutter lid can also cause to reject the component. If the shutter is bend downwards that it touches the component upon retraction, the flight distance of the component is directly proportional to the amount of shutter deformation.

reply »

Plasma Prior to Conformal Coating

Reflow Ovens thermal process improvement