Sponsor

Scaling SMT Traceability
High-mix electronics manufacturing requires precise material control. This whitepaper explains how Tecnimaster improved traceability, inventory accuracy and picking efficiency through integrated automated storage and reel-level tracking.
Essegi Automation

Sponsor

Viscosity Does Not Equal Rheology: What Solder Paste Measurements Really Tell You
Viscosity is a useful solder paste quality control measurement, but rheology provides a more complete understanding of how paste will roll, fill, release, recover, and remain stable during stencil printing.
AIM Solder

Ask the Experts

June 4, 2006 - Updated
July 5, 2007 - Originally Posted

Several questions including specifications for hole ratio and humidity control

A few questions.
1. What is the ratio of lead to hole diameter as per the standard? Which clause of the standard is applicable?
2. What is the standard temperature and humidity in the electronic assembly storage and assembly area? How best to maintain it? What are the tolerance limits? Which clause of the standard is applicable?
3. We can not use a wrist strap where the voltage is more than 80 VAC. Why? What are the technical reasons behind it?
4. What are the precautions to be taken while applying a peelable mask?
Thanks for your expert advice.

Veerendra Kumar Singh

Expert Panel Responses

I'll take the first one. Reference DOD-STD-2000, Volume 2A, 5.1.1.2.1 - 5.1.1.2.4 Round leads Maximum clearance, 0.028"/0.7mm Minimum clearance, 0.010"/0.25mm (of the maximum Lead Diameter) Rectangular lead Maximum clearance, 0.028"/0.7mm Minimum clearance, 0.006"/0.15mm (of the maximum diagonal/cross section of the lead)

Mel Parrish
FSO/Director Training Resources, STI Electronics Inc.

Mel Parrish is the FSO and Director of Training Materials Operations, Soldering Technology International (STI), in Madison Alabama. Before coming to the STI, Mel was the Training Manager for the Electronic Manufacturing Productivity Facility (EMPF) and President of Manufacturing Technology Training Center Inc. (MTTC) in Ridgecrest, CA. He remains active in industry trade associations and organizations such as IPC, SMTA, and SME.

Free Newsletter Subscription
Circuitnet is built for professionals who bear the responsibility of looking ahead, imagining the future, and preparing for it.

Insert Your Email Address

Sponsor

Gripping Systems from micro assembly to heavy lifting
The first industrial-suited grippers from SCHUNK were a milestone. Since then we have brought countless newly and further developments to market.
SCHUNK