Solving Cracking Issue in Acrylic Covers with a Material Change to PVC

Background Information

A manufacturer contacted us about a protective cover made from PMMA (acrylic) that was cracking around the screw holes. The cover was designed to prevent accidental contact during machine operation while allowing operators to see inside. However, repeated impact around the screw holes caused the acrylic to fracture over time.

Problem Statement

The customer needed a durable, transparent cover that could handle repeated use without breaking. While acrylic provided clarity, its impact resistance was too low. The challenge was to improve strength and reliability while keeping material and production costs under control.

Solution Implementation

We compared several transparent and translucent materials, including polycarbonate, PET, and PVC. Acrylic offered the least impact resistance, while polycarbonate provided excellent strength but at a higher cost. PVC struck the right balance—it was stronger than acrylic, reasonably priced, and clear enough for visual inspection.

To further strengthen the part, we considered replacing the screw joints with adhesive bonding, which would distribute stress more evenly and reduce the chance of cracking. After discussing the options, the customer decided to maintain the original design but switch the material from acrylic to PVC to minimize costs.

Results

Changing the material to PVC completely solved the cracking problem. The new cover offered higher durability, better impact resistance, and long-term cost savings by eliminating the need for frequent replacements. The client reported that the issue has not reoccurred since the switch.

Customer Feedback

“Our previous supplier had gone out of business, so we searched online for a new plastic processing company. We requested several quotes, but Yumoto Electric provided the most thoughtful proposal and seemed the most reliable.
The cracking problem has been fully resolved, and we can now operate with confidence. Thank you very much.”
(Manufacturing Industry / Tokyo)