The quality of the material and the design of the circuit board have a significant impact on the printing process.
- Board material should be as rigid as possible and stable in its X-Y dimensions.
- Coplanarity all across the board should be optimal.
- Milled openings interfere with board rigidity and X-Y stability.
- Hot air level finishing reduces the coplanarity of the pads (especially in fine pitch applications).
Uneven pad surface can cause loss of gasket seal resulting in bridging etc.
The thickness of the solder resist should be < the thickness of the pad.
If the resist is higher than the pad, the gasket seal will be lost resulting in bridging etc.
In fine pitch applications < 0.3 mm IC and QFP-configurations require an envelope
lay-out of the solder resist.
The registration of the solder resist relative to the pad should be centered.
Underside components can restrict the use of board support.
Large underside components may impede board transport-increase under clearance.
Via holes above suction cup cause loss of vacuum - move cup.
Labels, barcode stickers, registration marks, etc. increase board thickness leading to tooling, print and pressure problems.
Boards with tapered or chamfered edges are difficult to clamp and may be liable to movement during print leading to random offsets.
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