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Legend Print Clipping for Assembly
Introduction
Legend print clipping (legend) is a pre-production process that clips parts or completely removes a specific legend object(s) based on predefined rules.
Eurocircuits defined rules are:
- Legend Clipping for PCB Manufacture – Applies to all PCBs manufactured by Eurocircuits.
- Legend Clipping for Assembly – Applies to PCBs that are to be assembled by Eurocircuits.
To avoid legend clipping please follow the rule in our PCB Design Guidelines – Legend Print
IMPORTANT
- We strongly recommend that you follow the rules for legend placement as defined by your EMS partner, if it is not Eurocircuits.
Assembly Legend Clipping
The rules will be applied ONLY to those components placed by Eurocircuits Assembly service.
Why are there Additional Rules for Assembly?
Many issues connected to SMD component soldering are caused during the application of the Solder Paste.
Reasons for Assembly Legend Clipping
- Legend objects within the permitted clearance (as defined above) can cause bad solder paste application, especially for:
- Small SMD components
- Fine pitch SMD components
- SMD components with small connection pads
- Legend UNDER the body of an SMD component:
- Can cause Tombstoning on smaller components
- Can cause bad solder joints on components due to possible ‘none-flat positioning’ of the component on the PCB
Example of legend print between the component pads
The result – Tombstoning during the soldering process
The Rules – Assembly Legend Clipping
The additional clipping will be applied as follows:
- – All legend within +0.200mm of an SMD component’s physical body will be clipped/removed (including legend under the SMD body).
- – Any SMD component with a pad pitch of ≤0.400mm will have all legend clipped within a +2.00mm radius of each pad.
- – Any SMD components with a pad size of <0.32mm will have all legend clipped within a +2.00mm radius of each pad.
Original Legend as supplied in the Customer Data
Clipped Legend for Assembly
Approving the Assembly Legend Clipping
Before your assembly order is released for production you will receive a Pre-Production Approval (PPA) request.
The final production data can be then reviewed in the PCB Visualizer. The Compare Function of the visualizer will allow you to review and compare the original Legend data you uploaded with the production legend data.
Other ways to find help
Glossary
To simplify communication Eurocircuits uses abbreviations for many of these technical terms. Most of the technical terms and abbreviations are international standards in the Printed Circuit Board manufacturing industry. However to make it clear to everyone involved, we here present a list of technical terms and abbreviations along with their explanation.
Still need help?
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