How to control Machined Crimp Contacts – Under Size Conductor – CMA Buildup Crimps?
Let Top-cable tell you how to control it per IPC.
Target - Class 1,2,3
• The circular mil area of the conductor is built up so that it falls within the minimum and maximum CMA range of the contact.
• The CMA range is built up using one of the methods listed below:
• The conductor is folded or bent back to achieve the correct CMA buildup.
• The conductor area is increased by the use of bare (noninsulated) filler conductors as needed to achieve the correct CMA buildup.
• A combination of both the foldback and the filler method are used to achieve the correct CMA buildup.
• Special ''CMA Adapter Bushings'' are used when called out on the assembly documentation. (Use of these adapters will usually require special additional insulating coverage requirements.)
• The filler is visible at the wire entry end of the barrel.
Acceptable - Class 1,2,3
• The filler conductors and the wire conductor are visible in the inspection window of the contact.
• The filler conductor is of the same type conductor as the wire being crimped into the contact. (Gauge can be different as needed but the base metal and the plating if any needs
to be the same.)
Defect - Class 1,2,3
• A single solid conductor used to build up the CMA.
• The filler conductors and/or the wire conductor are not visible in the inspection window.
Defect - Class 2,3
• Fill wire extends beyond the insulation of the primary wire.
Defect - Class 1,2,3
• The flair or splay of conductor used extends past or exceeds the contact diameter.
• Exposed conductor violates minimum electrical clearance
