*Originally published January 21, 2003 by
Richard J. Ferenchick, VP Sales and Marketing
Arnold Industries is a distributor and supplier of fasteners, electromechanical products, specialty devices, and services sold principally to OEMs in the high tech arena. Founded in 1968 as a fastener distributor, Arnold Industries has evolved to be an integrated supplier of a wide variety of products. As a part of their wide offering of goods and services they provide many value added programs such as kitting, bin stocking, inventory management, and value analysis of complete assemblies.
Nidec/Power General is a manufacturer of ac-dc switching power supplies and dc-dc converters with power outputs up to 1KW. The company’s design and manufacturing center is located at 152 Will Drive, Canton MA. Nidec, a long-term account of Arnold Industries also located in Canton, was struggling with a nagging problem on a fairly simple assembly.
The application was attaching a TO220 packages to stamped and extruded aluminum heat sinks; the stack up typically included a “silpad” to facilitate thermal transfer, along with a fastener to complete the assembly. They were using a proprietary rivet which was unique to one supplier worldwide. The rivet was loaded onto a mandrel, which was then installed in a special rivet gun. The tooling required frequent maintenance. When malfunctions in product occurred the factory attitude was indifferent. Lead times were 16-20 weeks for product which required Arnold and Nidec to extend their inventory liability far beyond a safe level. The rivet was promoted as a product that could be removed and reinstalled but in actuality it was marginal in performance in reuse. Another serious problem was the high cost of the rivet (over $0.11 each). Constance Peacott, Purchasing Manager, and Shedrick Flynn, Buyer approached Arnold to help solve this problem.
Art Boyson of Arnold Industries evaluated the application and suggested a change in method by utilizing the Taptite II, a high performance thread rolling screw manufactured by Camcar Division Textron, Inc. of Illinois. This is a thread rolling screw that is licensed to several US companies and is priced at close to $0.04 each. The cycle time to install was identical, and the tooling for the Taptite was a standard pneumatic screwdriver. The larger diameter head allowed greater and more uniform clamp load and therefore more efficient thermal transfer.
While the concept was clear and simple, there were a few design constraints such as the fixed industry standard clearance hole in the TO220, heat sink, and silpad. The 0.060″ aluminum stamped heat sink required a balance between proper clamp loads; drive torque, and seating torque. The extruded product did not have that problem, but the task was to achieve a universal multi-function application solution. Art Boyson contacted Research Engineering & Manufacturing in Middletown, RI, the worldwide licensor of the Taptite screw to evaluate the assembly. Ken Gomes, VP of REMINC, suggested a #5-40 Taptite II screw after testing performance, which had all of the attributes required to accomplish the task.
At this point Arnold Industries suggested that the customer work with Arnold’s “Tiger Team” on a “Rationalization Program” that typically involves evaluating why each part is sourced where it is and why the vendor is the vendor of choice. Included also was a study of material movement on the factory floor. As a result of this study new vendors for each of the three parts were chosen and approved. Material costs combined with soft savings in material movement, purchasing, and quality control/incoming inspection can easily achieve savings of 40% of a manufacturing company’s total cost of material acquisition. At the same time, significant reductions in class C inventory can be realized through the relocation of inventory storage from the manufacturing floor back to the supplier. Daily manufacturing requirements may then be replenished by Arnold Industries as needed through shared weekly MRP reports. Since Arnold Industries supplies heat sinks, thermal transfer pads, and screws it was proposed by Arnold Industries to complete the assembly at Arnold Industries, supplying it complete rather than shipping in multiple parts and pieces. Nidec would receive one part delivered to the work cell on the floor by Arnold Industries rather than three (the TO220 would be supplied by Nidec) and by adding this to the Arnold Industries stocking program inventory would be reduced, and WIP would be eliminated. Production line problems, tool repair, etc. would be things of the past.
Documented results have shown, using one of the Arnold Industries inventory management programs, an easy 400% improvement in the number of inventory turns. Inventory management is relocated from the manufacturing company to the supplier without interruption in the manufacturing process. The supply line can be either manufacturing kits or work cell lot sizes.
Arnold Industries offers to evaluate any troublesome assembly, sourcing problem, or simply conduct a value engineering analysis of your current methods of assembly at no cost.