【170】Daily-Use Product Housing Cracking for Six Months – Fengchuang Solves It in One Order

【170】Daily-Use Product Housing Cracking for Six Months – Fengchuang Solves It in One Order

Keywords: Fengchuang Plastics, daily-use products, injection molding, parts and components

Mr. Zhang runs a storage box business in Yiwu. He has three stores on Tmall, and business had always been good. But last summer, a best-selling storage box started having problems – customers reported that after two or three months of use, the corners would begin to crack. The return rate spiked from 2% to 15%. Bad reviews kept coming in, one after another.

He went back to the original injection molding shop. They blamed the raw material. He switched to imported material – still cracked. Then they blamed the mold. Two rounds of mold repair – still cracked. He tried three different molding shops. Each one swore, "This time it will definitely be fine." And each time, it cracked. Six months passed. He had 80,000 housings sitting in inventory that he dared not ship. Customer service got cursed at every day. His store rating dropped to 4.2.

Mr. Zhang was so stressed that he couldn't sleep. He hadn't gone home for three weeks straight. He spent every day at the warehouse, staring at cracked housings. He went through his supplier list again and again. Finally, a friend in the appliance business said, "Try Fengchuang Plastics in Dongguan. They specialize in parts and components and work across many industries."

Mr. Zhang sent a cracked housing to Fengchuang. The Fengchuang engineer didn't rush to quote. Instead, he first cut the housing apart and did a material analysis. Half a day later, the phone rang: "The material is fine. The mold is fine. The problem is the design."

Fengchuang's analysis was this: the wall thickness at the four corners varied too much – 0.8 mm at the thinnest point, 2.5 mm at the thickest. During injection molding, the thin areas cooled first, the thick areas cooled later. The shrinkage rates were out of sync, and internal stress concentrated at the corners. After two or three months of use, the stress released – and the corners cracked.

The solution wasn't in the molding process – it was in the product design. Fengchuang recommended making the wall thickness uniform across the four corners, targeting 1.2 mm throughout, and adding R-corner transitions to eliminate stress concentration points. Mr. Zhang was skeptical but agreed to modify the mold. When the first samples came out, Fengchuang ran a one-week aging test to simulate three months of use. The housings remained intact.

When Mr. Zhang got the samples, he pulled them, stomped on them, and dropped them from height. The housings didn't budge. He then sent 50 samples to long-time customers for trial use. Three months later, he followed up – zero complaints. Today, that storage box has climbed back into the top ten of its category. Mr. Zhang has named Fengchuang a strategic supplier. He says, "Before, switching suppliers was about solving a problem. This time, switching to Fengchuang was about finding a partner who can solve problems alongside me."

Daily-use housing cracking? Fengchuang solves it in one order. We'll take your product from the complaint list back to the bestseller list.