|Ask the Experts|
July 2, 2007
Any "Standards" on pad repairs?
Is there anything in IPC or other Industry Standard that would indicate the number of pads that can be replaced and/or repaired on a multi-leaded component in a single instance? This would include epoxy as well as thermbond pad repairs.
|Expert Panel Responses|
A board needing to be repaired needs to be approved by the customer as it will not meet the requirements of the initial document. Per 7711, "Repairs are generally changes to an unacceptable end product to make it acceptable in accordance with original functional requirements. The control of repaired products should be by means of Material Review Board (MRB), or its equivalent, which may consist of Design Engineering, Quality Assurance, and User representatives. The MRB, with technical support, should define the mutually acceptable repair method to be used and take the action necessary to ensure that all applicable procedures are adhered to. The maximum number of repairs per printed wiring board assembly should be determined by the using activity or agency." So how many pads can be replaced, as many as the customer will allow and still have a reliable product. The other consideration is the cost of the product and the availability of meeting the time requirements to deliver the product to the customer. All these may be involved in the decision making process of repairing or replacing the product.
Vice President, Technical Director
I can't tell you how many times this question has been asked of us over the years. While the IPC 7711/7721 contains several procedures covering methods to follow to repair lifting or missing pads, it does not state, advise or recommend how many pad repairs are allowed.
Leo Lambert makes a number of excellent points in his response; the answer really boils down to what the customer will accept. We've had customers who will approve fifty or more pad repairs however we've also had other customers who will only allow up to two repairs and others that won't allow any.
Circuit Technology Center
|Submit A Comment|
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