3D printing has a lot to do with injection molding. Through this article, you can understand why 3D printing injection molds exist, and the process of making them. 3D printing injection molds to shape the future
What is a 3D-printed injection mold?
Injection molding is one of the most common manufacturing processes in the plastics industry. Essentially, molten plastic is injected into the mold cavity, allowed to harden as it cools, then the mold is opened and the plastic part removed. Injection molding is primarily used for mass production because of its high upfront costs in terms of design, testing, and tooling. Of course, the unit price drops dramatically the more parts are produced, which is the reason and advantage of using injection molding for mass production.
Why used 3D printing?
The injection mold itself is a block of metal with cavities that determine the shape of the product being made. Traditionally, molds are designed and produced by computer numerical control (CNC) milling machines, which are very expensive. Since molds are usually made of metals such as steel and aluminum, they are difficult to change once produced. Therefore, 3D printing injection molds offer a cheap and flexible alternative.
How to 3D print a mold?
1) Data processing
3D printing injection molds is done in a similar way to printing other 3D printed objects:
Injection molds are designed using CAD software such as AutoCAD or Fusion 360.
Design files are saved in STL format and sliced into G-code.
2) Use a 3D printer to print the mold layer by layer.
3) Mount the mold into the metal frame and prepare it for injection molding.
Materials for 3D printing injection molds require products with high strength and rigidity to withstand the pressure generated during the injection process. Also, it will need to be resistant to high temperatures.
The following are several commonly used materials for 3D printing injection molds:
PETG (polyethylene terephthalate)
ABS (Acrylonitrile Butadiene Styrene)
Nylon (aka Polyamide)
PP (polypropylene)
TPE (thermoplastic elastomer)
POM (Polyoxymethylene, aka Delrin or Acetal)
3D printing injection molds can be done using SLM, SLA, FDM, material jetting and SLS. That said, SLA is the preferred 3D printing method for producing injection molds due to the high dimensional accuracy and smooth surface that are ideal for injection molds.
There is one thing you should know about metal frames and their role in injection molds. The frame provides support for the pressure and heat generated during the injection molding process. Because the metal frame can be used universally, only the core part of the mold needs to be 3D printed, so changing the design is easy and flexible. However, in the case of 3D printing the entire mold, more material and longer printing times are required.
3D printing injection mold advantages and disadvantages
3D printing is an excellent option for producing injection molds, but it also has its drawbacks. The following comparison excludes metal 3D printing molds.
Advantage
1. Low cost: The traditional method of producing injection molds is very expensive and time-consuming, requiring precision machinery and expertise from the mold maker. And 3D printing is a cheaper way to make molds. According to reports, compared with traditional technology, 3D printing molds can save up to 80% of the cost.
Flexibility and efficiency: 3D printing drastically reduces design and production time. Anyone with 3D printing experience can print a mold, and if not happy with it, simply tweak the design and print another one.
2. Suitability for small batch production: The initial cost of injection molds made by traditional methods such as CNC milling is high. Therefore, it is only cost-effective if the output is large enough. On the other hand, 3D-printed molds are much cheaper to manufacture and are best used for small to medium-volume production without the high initial upfront costs.
Disadvantages
1. Longer production time: Since plastic has a lower thermal conductivity than metal, 3D-printed plastic molds take longer to produce products, extending overall production time and reducing productivity.
2. Shrinkage: Like many other 3D-printed objects, 3D-printed injection molds may shrink when cooled, which is a common problem in 3D printing. This can cause problems when exact dimensions are required.
3. Weak structural integrity: Most 3D printing molds are made of plastic, which cannot withstand high temperatures and pressure for a long time. This causes the 3D-printed injection mold to age at the gates and welds.
Frontier Research on 3D Printing Injection Mold
a. Surface coating
3D-printed injection molds are prone to degradation under high temperatures and pressure. Improving surface life with protective coatings is one way to prevent thermal degradation. Depositing a layer of metals, metal nitrates, ceramics, and oxides on the surface of a 3D-printed injection mold enhances its heat and tear resistance.
b. Thermally conductive composite materials
Thermal conductivity is a measure of an object's ability to conduct heat. Metal conducts heat better than plastic. In other words, metals can be heated or cooled faster than plastics. Since 3D-printed injection molds (molds) have longer heating and cooling phases than CNC molds, they also have longer cycle times. Only fewer products can be produced in a given period, and the production cost will increase compared with traditional metal molds. To solve this problem, thermally conductive additives are added to the mold material to improve the injection process. For example, boron nitride can be added to ABS and iron particles to epoxy.
Metal 3D printing injection mold
Metal conducts heat better than plastic, so why not 3D print metal injection molds? With recent developments in metal 3D printing, this is starting to see a lot of use as well. However, 3D printing metal is still much more expensive than plastic, so the upfront cost remains high.
Precautions for 3D printing injection molds
Before you start printing injection molds, consider the following helpful tips:
Print Quantity: Make sure you know how many to make! Keep in mind that 3D printing injection molds are only for small batches (30 to 100, depending on the mold). So if you plan to make thousands, you might want to consider regular molds.
Add a draft angle: Right angles can make injection molded parts difficult to come out of the mold, so try adding a 2-degree draft angle to make the object slide out easier.
If you also need this convenient 3D printing main complaint mold, you can contact JR Technology Company, we can provide you with professional guidance and high-quality products. Contact as below:
Contact Name: Joy
Telephone Number: +8618682431494
Email:sales@china-3dprinting.com