Plastic Mold Technology and Hot Runner Principles: What Are They? (Part 4)

A cup holds stories, and life carries warmth. Hello everyone, "Dong Dong's Cup Talk" is here! Most friends who follow me know what industry I’m in. http://www.zhanyict.com/en/ProductsDetail-VB-10505.htmlYes, I’ve been working in the water cup industry for many years. But actually, the factory I work at doesn’t just produce various stainless steel cups and insulated tumblers—we also make all kinds of plastic cups and sports bottles.

Naturally, our factory is also capable of producing various plastic molds. Today, I’ve invited Mr. Feng, a professional with over 20 years of experience in plastic mold development at our factory, to share with us: What are the key plastic mold technologies? http://www.zhanyict.com/en/ProductsDetail-VB-10505.htmlAnd what is the principle behind hot runners? Since there’s a lot to cover, I’ll break it down into four parts.

IV. How to Quickly Assess Mold Difficulty and Cost?

(Engineer’s Quick Judgment Rule: Structure depends on parting lines, http://www.zhanyict.com/en/ProductsDetail-VB-10505.htmlcost depends on steel and lifespan.)

Difficulty Assessment:

- Simple Mold: Flat parting line on a cup lid, no side core pulling (Difficulty: ★, Cost: 100,000–150,000 RMB).

- Medium Mold: Shell with curved parting line + http://www.zhanyict.com/en/ProductsDetail-VB-10505.html2 sliders (Difficulty: ★★★, Cost: 250,000–400,000 RMB).

- Complex Mold: Micro-threaded cup lid + gas-assisted molding (Difficulty: ★★★★★, Cost: 800,000 RMB and above).

Cost Breakdown:

- Materials (30%): S136 steel is 2–3 times more expensive than P20.

- Processing (50%): http://www.zhanyict.com/en/ProductsDetail-VB-10505.htmlMirror polishing labor costs can reach 200 RMB/hour.

- Hidden Costs: Each additional slider increases costs by 50,000–80,000 RMB.

V. Practical Takeaways

- Hot Runners Aren’t Always the Answer: For small-batch orders, three-plate molds are more economical (mold price difference: 100,000 RMB vs. hot runner system cost: 150,000 RMB).

- Failure Is the Best Teacher: http://www.zhanyict.com/en/ProductsDetail-VB-10505.htmlA cup lid project once lacked mold modification tolerance, leading to three revisions and a 45-day delay—now all designs must include a "±0.1mm process adjustment zone" note.

- An Engineer’s Bottom Line: No matter how urgent the project, mold flow analysis and T0 inspection checklists must never be skipped!