Hello and welcome to a new blog post. Today we dive into the optimal tool making for Polyarylamide parts.
Designing and producing injection molding tools for Polyarylamide (PARA) is both an art and a science. This high-performance polymer offers outstanding mechanical properties and surface aesthetics—but only if your tooling is up to the challenge!
Here’s a deep dive into the six essential steps for success (Figure 1):
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| Figure 1: Overview of the six steps of tool making for molding Polyarylamide (PARA; MXD6). |
1️⃣ Part Design: Build on Solid Foundations
- Use generous radii (≥0.6 mm) to reduce stress and ease ejection.
- Apply draft angles: at least 1° for polished, up to 3° for textured surfaces.
- Optimize gate placement and size—locate at the thickest section, with land lengths of 0.8–1.6 mm.
- Take advantage of PARA’s low shrinkage (0.20–0.25%) for tight tolerances and minimal sink marks.
- Simulate your design (Moldflow®, Flow-3D®) to predict flow, weld lines, and optimize geometry.
2️⃣ Mold Definition: Specify for Performance
- Select abrasion-resistant steel (≥54 HRc) like Stavax ESR or Orvar Supreme to withstand glass fiber wear.
- Design for “steel safe” dimensions—easier to remove than add steel!
- Ensure robust venting (max 0.01 mm) and cooling (10 mm channels, 15–20 mm spacing).
- Use hot runners for efficiency and consistent quality.
- Calculate clamping force: 1 ton/cm² of projected area.
- Add cavity pressure sensors for processing optimization, especially with multi-cavity tools.
3️⃣ Detailed Drawings & Production: Precision Matters
- Prepare comprehensive technical drawings with all tolerances and features.
- Plan for heat treatment and machining—every detail counts for tool longevity and part quality.
4️⃣ Cutting Steel: Prepare for the Long Haul
- Mill, heat treat, and quench your steel to achieve optimal hardness.
- Allow for deformation during heat treatment (“steel safe” approach).
- After treatment, remove any brittle, oxidized layers by sandblasting to prevent future tool issues.
5️⃣ Assembly & Testing: Fine-Tune for Perfection
- Assemble and adjust all tool components, ensuring smooth operation.
- “Blueprint” the tool at low clamping force to check split lines and prevent flash (PARA has good flow properties, similar to PPS).
- Design for easy maintenance: include features like mold centering adjusters, ejector return pins, and replaceable components.
6️⃣ Polishing & Surface Treatments: Finish Strong
- Polish all surfaces to ensure easy part ejection and premium aesthetics.
- Apply specialized surface treatments to extend tool life—especially important with glass-filled PARA.
Pro Tip:
PARA’s high flow and low shrinkage enable thin, complex parts with exceptional surface quality. But to fully leverage these benefits, every step of your tooling process must be meticulously planned and executed.
Are you working with PARA or considering it for your next project? Let’s connect and share best practices for robust, reliable, and beautiful injection-molded parts!
More on PARA here:
Design Properties for Engineers: The ABCs of Polyarylamide (PARA; MXD6)
Thanks for reading & #findoutaboutplastics
Greetings,
Literature:
[1] Syensqo - Ixef PARA Design Guide
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