Often times when designing a bolted joint we try to use standard, off the shelf fasteners for the lowest cost, but the cost of the entire assembly is not considered. Take the example below found in an electric lamp:
Conventional Fastener Solution
Here we have three fasteners, a machine screw threading into a clinch nut, and incorporating an external tooth lock washer to create a good ground for a ring terminal. Seems like a pretty good, cost-efficient joint, right? But let’s look at another possible solution:
Multi-Functional Fastener Solution
This solution incorporates a multi-functional thread forming screw with nibs under the head to create our needed grounding contact. The screw itself is more than three times as expensive as the machine screw above. If we look at the total cost of the assembly, we can see the savings.
|Fasteners/Assembly||Machine Screw||Thread Forming Screw|
|Screw M4 x 8||$1.36/C||$4.50/C|
|Clinch nut M4||$10.41/C||n/a|
|Assembly of nut||$17/C||n/a|
|Mfg of pilot hole||$14.88/C||14.92/C|
|Toothed lock washer||$1.02/C||n/a|
|Assembly of washer||4.25/C||n/a|
The multi-functional fastener solution results in a 60% cost reduction over the conventional solution.
Bossard offers Expert Education seminars as webinars or in person at your facility, tailored to your specific questions and needs. For a full seminar on Cost Efficient Assembly, contact us at ProvenProductivity@bossard.com.How to Cost Efficiently Design a Bolted Joint by Bossard