About this site
Think Plastics is a set of practical, sourced answers about injection moulding, covering mould cost and life, tooling time, and design rules for walls, draft, ribs, tolerances and shrinkage, plus material choice and press size.
How the articles are written
- Each article answers one question. The first sentence gives the short answer; the rest explains how to apply it, and the article ends with common buyer questions.
- Figures come from named public sources, such as material and moulding suppliers' design guides and published standards. Each article lists its sources at the end.
- Where sources disagree, the article says so rather than picking one quietly.
- Numbers are typical planning values, not quotes or specifications. Check them against the data sheet for your exact grade and with your toolmaker.
What the articles cover
- Cost and volume: what a mould costs, which production volumes suit moulding, and how many prototypes to plan before tooling.
- Tooling: how long a mould takes to build and how long it lasts, aluminium against steel, and what size of press a mould needs.
- Part design: wall thickness, draft, sink marks, tolerances and shrinkage.
- Materials: the most common moulding plastics and how to choose between them.
How to use the figures
Use the published ranges to plan, to sense-check a quote, and to prepare questions for a toolmaker. Do not use them as a specification. Each article closes with questions buyers often ask, and the answers point to what to confirm in writing with the supplier.
Who runs this site
This site is run by WJH & JCH Global Trading (JCH). We design injection molds, manage tool life, and match projects to qualified third-party factories.
One article, on mould cost, links to the company's website. That is the site's only commercial link.