Colour & Injection Molding

“You shouldn’t judge a book by its cover” is a saying that is drilled into all of us from an early age: it is a noble sentiment and something that we should all strive to live by. However, unfortunately, it does not apply to the world of manufacturing: no matter how good and useful your product is, consumers place a high value on its appearance. If your new product is going to be a success you have to nail the aesthetics.

Getting them right can be a complicated and difficult process in plastics manufacturing and may involve artists, designers and mathematicians to name but a few. Not many people, however, believe that choosing the colour is a potential issue – they tend to think that once you have found the right manufacturer, you simply show them the colour that you want and they go off and do it. Unfortunately, mixing colours for plastic injection molding is actually far more difficult than you might think, and there are a few things that all designers and entrepreneurs need to know before embarking on the process. Luckily, we at HLH are here to help and our friendly team of experts has come up with a list of everything that you have to take into account now, to avoid disappointment later.

Here are your 4 choices and the pros and cons of each one:

Compounded Colors

Compounded colours (also known as pre-mixed) are made, by the resin supplier: to do this they blend together the colour pigment and the raw material to produce small plastic pellets, which are then ready to be injection molded. The advantage of using this method is that it produces the most consistent colouring time after time; and is the best way to colour materials with a dense base colour, such as fire retardant plastics. It is probably the cheapest and easiest method for common colours and most manufacturers will find it easy to procure them. However, if you want a custom or unique colour it may be more difficult: the resin supplier will only be willing to compound such a colour for orders of more than a ton, meaning that it may be expensive for smaller orders.  At HLH we are committed to finding the right molding solution for you, so contact us today to find out more about our compound colour solutions and whether it is the right choice for your business.


The resin supplier also produces masterbatched colours: to do this they create heavily pigmented plastic pellets, with a ratio of 50% colour to 50% resin. We then mix them with uncoloured plastic, before they are injection molded, which creates a ratio of 2% colour by volume. It is more difficult to achieve the correct colour consistency with masterbatching, but at HLH we have the equipment and the expertise to overcome this potential problem. Generally masterbatching is better for larger runs as it is more cost-effective than compounding, however, it is possible that the overall colour quality will suffer slightly. At HLH we are proud of the injection molding services we offer, so contact our friendly team for more help on the right process for your business.

Solvent Coloring

With this process, we mix pigmented oil with a solvent and then spray the resultant mixture over uncoloured pellets, just prior to injection molding it. The advantage of doing this is that it is more cost-effective; however, it can sometimes be difficult to precisely manage the ratio of colour to plastic, even with HLH’s state of the art technology. It is a great option for smaller businesses that are just starting out and may not be ready for a huge order (just yet). So contact our friendly team of experts at HLH today, to see what solvent colouring can do for your business.

Dry Pigment Mixing

In dry pigment mixing the powder is mixed directly with the plastic pellets inside the hopper, again aiming for a ratio of 2% pigment by volume. The problem with this is that it greatly increases the variables: sometimes the pellets have to be dried before the process; sometimes the pigment can stick to the walls and plumbing of the hopper; sometimes water vapour will enter the mixture once it has been taken out of the dryer. All of these variables mean that it is difficult to guarantee the quality of colour that we would like to: our expert team will endeavour to provide you with exactly the colour you need (and we do manage it often), but in some cases the quality of the colouring does suffer. Which is why we recommend it for small orders: either to create a part that is too small to be compounded or for businesses that are just starting out. At HLH we are masters of our field and are committed to finding the right manufacturing solution for our customers: so contact our friendly team today, to see how we can help you.

Over to you

At HLH we will always strive to find the most cost-effective colour solution for you: the closest possible match at the best possible price. However, in prototype or low volume manufacturing compromises may have to be made, especially when you need a particular custom colour. With large volume orders we can always guarantee the best possible colour consistency, but smaller quantities can sometimes vary.

At HLH we are proud of the service that we offer and always seek to find the best possible solution for every customer. We combine state of the art technology, some of the foremost experts in the field and outstanding customer service, to ensure that we provide outstanding manufacturing solutions across the board. So contact us to see how we can help you nail the aesthetics of your product. – At HLH, we make things for you.


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