While it’s natural and entirely understandable for most plastic injection molding clients to be primarily focused on the properties and functionality of their designed parts, there are also some important aesthetic considerations to keep in mind here as well. One such area that’s worth paying attention to for any plastic injection molded product: The finish that’s used.
At EnviroTech Custom Injection Molders, we’re here to offer the very best plastic injection molding services for numerous industries, from food processing to marine, medical, oil and gas areas and more. What are we referring to when we talk about the finish on any plastic injection molded part, and which finishing options are available for most such products? Let’s take a look.
What is Plastic Injection Molding Finish?
When we talk about finish, we’re referring to a few different approaches that are used to create the final look of a given part. The goal here will be to make the part look appropriate while also reducing any kinds of blemishes or inconsistencies that might be visible to the naked eye.
These finishes will be applied using a few different materials and formats, depending on the precise need. Various finishes are categorized into different grades by the Society of Plastics Industry (SPI), which technically has 12 separate grades it can use for this purpose.
However, we don’t really need to go over all 12 of these for you to understand some basics on injection molding finishes. Our next several sections will go over the four general groups that these grades can usually be placed in, plus what to know about each one and why you might consider it.
For those looking for a smooth, shiny finish to a given part, the “shiny” category is the way to go. Referring to finish grades A-1, A-2 and A-3 within the SPI’s grading list, these finishes create a mirrored-like look that’s very aesthetically pleasing.
However, they are also more expensive than other kinds of finishes due to the amount of work and additional processes employed in their creation. In addition, these particular grades tend to be less durable than many others, despite the lack of imperfections.
For those wondering how this is done, the shiny finish is accomplished using a diamond powder suspended in an oil solution. You’ll often see these kinds of finishes used in products like mirrors, optical parts, jewelry and even some watches.
A finish that’s similarly smooth to the shiny option, but does not have the same level of shine or reflection, is the semi-gloss finish, which covers grades B-1, B-2 and B-2 from SPI. These grades range from medium to medium-low in polish, whereas shiny finishes will be high in polish factor.
Semi-gloss is a very popular style because it meets multiple needs and comes at a relatively low price compared to the shiny finish. It’s also very durable and versatile, able to stand up to many conditions without losing its overall appeal.
It’s usually applied by using some of the same methods as other finishes – an oil-based material suspended with a similar solution will be used in order to get this kind of finish. It’s commonly used in areas like appliances, automotive parts and even certain items of clothing and upholstery.
Created using a fine stone powder rather than any kind of liquid solution, matte finishes are categorized from C-1 to C-3 by SPI. These are known for their price and durability, as well as the fact that they’re generally very resistant to staining.
This is because matte finishes tend to cover a wider range of applications than other grades. They are often used in areas like labels or identification cards, package inserts, printers and even some electronics or medical devices.
Similar to the semi-gloss finish, but with even greater smoothness and shininess, gloss finishes are also a good option for most plastic injection molded products. Many of these products will be similar to shiny finishes in several ways.
While somewhat more expensive than other kinds of finishes, glossy is still a very versatile option that’s often used in areas like furniture, automotive parts, bath and kitchen fixtures and even some toys. It’s also commonly found on items of clothing, cosmetics packaging and other products where a high-end appearance is desired.
Finally, using processes like sandblasting and others meant for roughing up a given product, the dull finish is considered to be an excellent choice for plastic products that will be used in areas like electronics. This type of finish can also vary from very low to high in terms of its level of smoothness, depending on what was done during the production process. It’s often found on medical devices and some kinds of packaging or cooking appliances.
Which kind of finish you choose for your plastic injection molded product will depend on a number of factors, including the specific use for the piece, how much durability it needs and how much shine is desired. It’s also important to keep in mind which types are most popular in certain applications so that you can stay up-to-date on current trends.
And if you need any assistance with this or related areas of the plastic injection molding world, our team at EnviroTech Custom Injection Molders is here to help. Please don’t hesitate to contact us today for further guidance on any of your needs!