Although injection moulding creates more waste than 3D printing, it's still one of the least wasteful manufacturing processes for plastic, and for large-scale production, it's much faster and more efficient than 3D printing. However, if you truly want to minimise waste during the process, you should check out the following tips.

Use Thermoplastics

With injection moulding, you can use thermoset materials, but thermoplastics are superior if you're trying to minimise waste. To explain, thermoset materials can be cured once. If they melt after that point, they won't be reuseable. In contrast, thermoplastics can be heated, cured or set, and reheated multiple times. Those properties minimise wasted materials. If there are materials left over after filling the mould or even if you scrape off extra bits of plastic after pulling the product out of the mould, you can remelt and reuse that plastic if you're using thermoplastics. 

Work on the Prototype Using 3D Printers

With injection moulding, it's easy to scale your project up and create more, but it's challenging to set up the project. As a general of rule of thumb, you face relatively high startup costs with injection moulding, but the overall production costs stay low during the project. That said, if you want to minimise wasted financial resources, you should ensure the prototype meets your needs before you start manufacturing it with injection moulding. Arguably, the easiest way to do that is by creating your prototypes with a 3D printer, ironing out the issues, reprinting as needed, and the finally turning to injection moulding when you've settled on your final design. 

Start With Large Cavities Moulds

Once you have your design solidified, you need to make 'tools', which are metal parts of your mould. If you're making anything with a cavity, you may want to start with more metal for the cavity that you need. To explain, imagine that you are setting up an injection moulding project to make plastic caps for bottles. The metal is going to be shaped in a way that creates the cavity of the cap. If you make the metal for the cavity too large, you can easily cut away metal to make the cavity smaller, but if the metal is too small, it's challenging to add more metal, and that adds time and extra cost to your project. 

Fit the Moulds Together Tightly

In general, using moulds minimises waste. For instance, if you use CNC machining, the machine carves away plastic, leaving a lot of scraps in its wake. In contrast, with injection moulding, the small amount of wasted material usually only surfaces if there is a bit of overflow in part of the mould or in one of the corners, but a quality professional with extensive experience in injection moulding can make sure that two sides of the mould fit tightly together and take other steps to minimise waste. 

To learn more, contact an injection moulding professional directly. They can answer your questions about how to minimise waste.