Xometry.pro
en – TR
Knowledge & Community
Quote & source your parts
Europe Europe
English Deutsch Français Italiano Español
Türkiye Türkiye
English Türkçe
United Kingdom United Kingdom
English
Global Global
English

Get Instant Quote

Use our Instant Quoting Engine to easily quote and source your parts online

Get a Quote
Back
 Profile
Menu
Materials Library
Articles
E-Books & Guides
Manufacturing Stories & Cases
Free Tools
Webinars
Free Courses
Community Discussions
Create Topic
Quote & Source Your Parts
Get a Quote

Edit topic

Home Xometry Community Industrial Design Design tips for living hinges for plastics

Design tips for living hinges for plastics

0
D
7

Hey. I’m working on an insecticide sprayer, using a living hinge battery compartment. I’d like thoughts on design and durability issues. I know material selection is a big deal – it needs to be tough, flexible and durable. What about Polypropylene? It’s supposed to have a good fatigue resistance and it’s not expensive.

Link copied
    • D

      Hey. I’m working on an insecticide sprayer, using a living hinge battery compartment. I’d like thoughts on design and durability issues. I know material selection is a big deal – it needs to be tough, flexible and durable. What about Polypropylene? It’s supposed to have a good fatigue resistance and it’s not expensive.

      0
      Reply
    • C

      Agree. Live hinges work well in polyethylene, but not for cosmetic products. PP isn’t really an engineering material and it’s tricky to get great finish – pick an experienced tool designer/molder. 

      The thickness is also crucial. Start about 0.2 to 0.4 mm. I like to start the tooling with the hinge at the thinnest, as the thicker the metal off the tool, the thicker the metal.

      0
      Reply
      Link copied
      • D
        Christoph

        How do you ensure the hinge’s durability? This one won’t see huge cycles.

        0
        Reply
        Link copied
      • C
        Daniel Harris

        A parallel hinge will crack sooner than a tapered one. Smoothly thinning towards the center will reduce stress concentration.

        Consider the bent radius of the hinge. A longer flange reduces the stress. Avoid all sharp transitions in the flex area. A bend radius of 0.25 to 0.5 times the hinge thickness is good.

        0
        Reply
        Link copied
      • C
        Daniel Harris

        Also avoid positioning it near areas of high stress. Keeping the hinge away from turbulent flow will allow better chain alignment, which improves crystallinity. Turbulent flow will make the flex part amorphous/fragile.

        0
        Reply
        Link copied
      • D
        CommunityMember

        Good point. He’s the model I created following these design tips. Now I want to make sure the molding process of the live hinges will be flawless. 

        0
        Reply
        Link copied
      • C
        Daniel Harris

        Finite element analysis can help in the design phase. It will tell you about flow. Simulation can prevent mistakes and allow you to tweak the design before tooling. This saves a lot of time and risk, particularly because you can’t trust prototypes. 3D printed and machined parts cannot give the right material properties in the flex area.

        0
        Reply
        Link copied
      • D
        CommunityMember

        This is really helpful, thank you. I’ll also run flexing tests for the hinge to confirm it can withstand repeated use.

        0
        Reply
        Link copied
Design tips for living hinges for plastics
Your information:




Suggested Topics

Topic
Replies
Views
Activity
Optimizing support structures for DMLS printing
Industrial Design
Hello everyone, I’m working on a DMLS turbine blade with some overhangs and complex curvature, and I’ve run into challenges with support structures. I’ve noticed that removing the supports leaves marks and sometimes even... read more
T
a
1
22
Oct 14
Curved features on 3-axis vs 4-axis CNC machine
Industrial Design
Hello, I'm trying to better understand when a 4-axis CNC machine is necessary for machining curved features. I know that a 3-axis machine can handle some curved cuts, but I’ve heard that certain designs... read more
M
J
1
27
Oct 08
Do low-tolerance features need to be dimensioned on drawings?
Industrial Design
Hello, I'm working on a project that needs a lot of precision, and I’ve always thought parts should be fully reproducible from the technical drawings alone, without needing a 3D CAD file. Lately, though,... read more
T
C
M
2
32
Oct 09
Interpreting GD&T in high-precision drawings
Industrial Design
Hi, I'm currently designing high-precision parts that require detailed GD&T specifications and I'm concerned about how well my design intent will be understood by manufacturers. What are some of the most frequent issues you've... read more
A
C
1
35
Sep 27
Optimal shore hardness for snap-fits in electrical housing
Industrial Design
Hello, I'm designing snap-fit features for a small electronics housing made from PA12 (Nylon) and need to ensure the material provides the right balance of flexibility and durability. The snap-fit will be used for... read more
M
T
1
50
Sep 12

Edit topic