Moulds: 3D Printed Resin

A complete guide on how to prototype your own 3D printed resin moulds and how they compare to our Premium Aluminium moulds.

 

Introduction

One of the main barriers to entry in designing recycled products is the ability to get cheap and reliable moulds. Although Sustainable Design Studio makes custom affordable aluminium moulds on demand we understand that this isn’t an option for everyone. Even more so if you just looking to test out a prototype design. That’s why Stereolithography (SLA) high-temperature resin for creating injection moulds is gaining attention as a versatile alternative to traditional aluminium moulds.

In this section we will delve into the advantages and disadvantages of employing SLA resin in the mould-making process, offering a fresh perspective on efficiency, cost, and quality. We'll explore a step-by-step guide on how to craft these innovative moulds and compare them to their aluminium counterparts to help you determine the best approach for your specific needs in product development.

Getting Started

You will need:

Optional Extras:

  • Fine Grit Sandpaper (800-1200grit)

Make sure you don’t mix up SLA with the more common FDM printing. FDM melts plastic in layers to create objects, SLA uses a chemical reaction to “cure” the plastic. As a result SLA prints are heat resistant, FDM is unfortunately not!

The Pros & Cons of Resin Prints

  • Pros

    1. Relatively cheap to make.

    2. 3D SLA Printers are readily available.

    3. A new mould can be made in as little as 5-6hrs.

  • Cons

    1. Limited to less than 100 injections before the mould deteriorates.

    2. The mould takes longer to cool than Aluminium, slowing down production.

    3. Flashing is a major issue due to the softness of the material.

    4. A resin mould cannot warmed up for easier material flow.

    5. The moulds are less accurate, as a result, more post-processing is required.

    6. Not great for small or detailed items. Such as text.

FAQs

  • Several reasons. Firstly when injecting the plastic it requires a huge amount of force, that would destroy the cured High Temperature Resin if injected into without the frame. Secondly, the frame acts as a buffer between the hot nozzle, and resin. Increasing the life of the resin mould and ensuring it can be used as much as possible before breaking.

  • Yes, due to the nature of the mould being more delicate than an a full aluminium mould, its best to avoid using them for objects with fine detail such as small text or intricate logos.

    Best to stick to larger and thicker items or accept that you may only get a few injections before these details are lost.

Step 1

Select the item you would like to inject. In this guide, we will be using a “Low Poly” themed chess piece that has been specifically designed to be injection moulded. It has also been scaled to specifically fit our Medium-Sized Resin Mould Holder.

Step 2

Because we are using the Medium-Sized holder we will need to place 50% of the piece into one-half of the resin mould, and the other 50% in the other half to create our negative cavity space.

Step 3

With the item located, we now need to choose an entry point for the plastic. The hole for the mould is 6mm, and we have chosen a taper of 3 degrees to reduce the size of the sprew to a diameter of 3mm at the point it meets the chess piece.

Step 4

Due to the nature of the resin mould, and the fact the resin is relatively expensive, we encourage you to use a hexagonal pattern to reduce the amount of resin required to make the mould without reducing the durability of the mould.

Around all areas of the injected item, there is still a thickness of at least 3mm.

Step 5

Once we have our design, we need to export it into the relevant 3D Print Slicer. In this case we are using Chitubox. We then import the 2 halfs of the mould and rotate the items 45degres. This will ensure the moulds are successfully printed. Then following the specific printer guidelines and resin cure times, we adjust the paramaters for printing and slice/export the code to print the resin moulds.

Step 6

Once printed we need to complete the standard post processing such as washing, removing support and UV curring. Please folllow the machine and resins standard guidelines when doing so.

Step 7

The washed and cured items should look something like this.

Step 8

Once cleaned up you should be ready to install the resin moulds into their holders. They should be a snug fit, but shouldn’t be forced.

If its too tight to press in, then you may need to sand of any protuding edges with 800 or 1200 grit sand paper.

Step 9

A small gap is allowed, but if needed you can use small bits of paper, acting like shims to reduce this. Focusing on ensuring the entry point of resin mould aligns with the aluminium injection point.

Step 10

Injecting into these moulds is almost exactly the same as an Aluminium Mould however here are some tips:

  • Reduce the injection pressure as much as you can to avoid flashing.

  • Using the lowest temperature setting for melting the plastic will increase the life of the mould.

  • Use a silicone release spray to prevent damage to the moulds and reduce sticking.

  • Let the product cool inside the mould before removing it (opposite to aluminium moulds).

Step 11

Hopefully, after following these steps (and a little bit of a cleanup) you should have a fully recycled and freshly injection moulded product!

What will you create?

Important Usage Tips

  • The mould is heat sensitive and deteriorates faster with higher temperatures. To ensure a long life always inject at the lowest possible temperature that allows you to achieve good results.

    We use 200c for PP.

  • Lower the pressure of the injection for the IMM using the gauge on the left hand side. Do not use the max pressure like the aluminium moulds as this can easily break the mould.

    We use around 80psi for PP.

Related Resources.

  • 3D Printing vs Injection Moulding

    3D Printing vs Injection Moulding

    A full break down on the advantages and disadvantages of Injection Moulding when compared to 3D printing.

    Learn

  • Mould Use

    Everything you need to know about how to use our moulds and deal with common problems.

    Learn

  • How To Inject PLA

    How to convert 3D printing waste into eco-friendly products with our injection mini

    Learn

  • How to 3D Print FDM Moulds

    A guide on how to 3D print a mould using FDM printing and what you need to do it yourself.

    Learn

  • Good Product Design

    A comprehensive guide to what makes a good, and bad recycled product.

    Learn

Make sure to share your creations with us on social media, we love seeing what you all create!

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