Plastic injection molding has been around for more than a century. Over the years, technology has developed. Many improvements were made throughout the twentieth century that allowed molders to produce more detailed parts of a higher quality. Everything from injection molding machines to the polymers used was changed and, subsequently, parts could be better suited to their final use. A versatility was born that has largely revolutionized the uses for plastic injection molding.
But in more recent years, plastic injection molding has no longer been the talk of the town for plastic part manufacturers. A lot of focus has shifted to 3D printing as a viable, affordable and versatile means of manufacturing plastic parts.
What Is 3D Printing?
With 3D printing, it’s now possible to make plastic parts almost completely from scratch. The first part of the process involves designing the part you wish to manufacture using a computer aided design. This design is usually done using 3D modeling software, or can be done using a 3D scanner.
Once the 3D design is complete, plastic parts are then produced from computer file with the design. This allows for exactness in the design you make. The part is made by successively applying many thin layers of material until the part is complete.
And while 3D printing is definitely a good option in some cases, plastic part manufacturers should be aware of the limitations that 3D printing still has when compared to injection molding.
Advantage Of 3D Printing
One area where 3D printing has been far superior to injection molding is when manufacturers only need a small quantity of a part. Injection molds are expensive tools, but with 3D printing, a special printer doesn’t have to be made every time a part is needed.
Depending on the part that’s being produced, the point at which plastic injection molding and 3D printing breaks even will vary. Generally though, it’s safe to say that 3D printing will always be cheaper if 250-300 parts are required.
The problem is that the cost per part of 3D printing will remain reasonably static, regardless of how many parts are required, while injection molding proves to be a good long-term investment. With plastic injection molding, one mold can produce more than a thousand parts. The initial investments to buy a mold will be costly, but as the mold keeps producing parts throughout its lifetime, the price per part can drop considerably. Some parts can even be manufactured for less than $2 each.
If you would like to get an idea of the cheapest option in your case, there’s a quoting engines available online that are able to give you a rough estimate of where costs will break even.
Injection Molding Is Still Superior
While injection molding has only emerged in the last few centuries, the concept of molding is ancient. That’s why it might come as a surprise that a technological concept that’s so old can still be the best option in modern times.
But don’t underestimate the technological advancement of the plastic injection molding industry. The concept of molding might be ancient, but the technology used to produce molds is far from primitive. Modern molds can accurately produce parts down to a fraction of a millimeter if necessary. Specialists meticulously polish molds to create smooth surfaces. Because of this, molded parts still have a smoother appearance than 3D printed ones.
The other benefit of plastic injection molding is that manufacturers will have a wider range of materials to choose from. 3D printing is still developing to allow for more choice in materials. In the future there will be more materials that can effectively be used for 3D printing, but as things are now, plastic injection molding is still by far more versatile in this regard.
When to Choose 3D Printing
It’s clear that plastic injection molding is better when large quantities of a part will be made and when manufacturers need a part that will be of a higher quality. Despite this, there are still cases when 3D printing can be a good option. The technology is still developing and could become more practical for mass production in the future.
Right now 3D printing is a good option if it’s the cheaper way to produce a part. Sometimes having a plastic injection mold made is unpractical, as manufacturers only want a small quantity of a certain part. However, 3D printing won’t be able to produce any part a manufacturer might wish to make.
What’s clear is that 3D printing won’t be taking over injection molding in the near future. Molds still have produced more parts that are of a higher quality in less time. As mentioned, cost per part breaks even with 3D printing at only 200-350 parts, making injection molding the obvious choice for large scale industrial manufacturers.
3D printing is an exciting development in plastic part manufacturing, but it’s still got a long way to go before it can realistically compare to injection molding when manufacturing large quantities.
Injection molding is still the best option in most cases. Currently 3D printing still proves not threat to the plastic injection molding industry. Without a doubt, medium to large scale manufacturers will still choose injection molding over 3D printing. The tighter tolerance and lower production cost makes it the clear choice.