As 3D printing technology matures, it continues to impact various industries, such as model manufacturing. Some injection mold enterprises claim that 3D printing mold is 90% faster and 70% cheaper than traditional mold processing. Is this true? Let's see what everyone thinks.

 

Additive manufacturing, also known as 3D printing, has had a huge impact on manufacturing. Hand-made pieces that once cost hundreds of thousands of dollars and took weeks can now be designed in the morning, printed at night and delivered to customers the next morning.

Some companies are already using 3D printing to make injection moulds. In contrast to traditional mold manufacturing, 3D printed models no longer require months of waiting for a mold to be manufactured that is ready for production, or a lot of money to be spent modifying the mold due to downstream design changes, or uncertainties at the production level. Whether it is mold verification or small batch production of injection parts, it can quickly 3D print molds. If there is a problem with the mold or the design needs to be modified, print another one and repeat validation or production. Because of these advantages, many enterprises choose to introduce 3D printers, which is also the advantage of 3D printing molds.

3D printing molds have their own place, and some enterprises are more successful in the application of 3D printing molds. Therefore, some enterprises claim that 3D printing molds are 90% faster and 70% cheaper than traditional mold processing methods. This may be true in some cases, but it's also important to understand the advantages and disadvantages of traditional molds compared to 3D-printed plastic molds.

Advantages and disadvantages of traditional mold compared with 3D printed plastic mold

Surface quality: 3D printing produces parts layer by layer, which results in a step pattern effect on the surface of the product. A similar problem exists with direct-printed molds, which require later machining or sandblasting to remove these fine, toothed edges. In addition, holes smaller than 1mm must be drilled, larger holes must be reamed or drilled, and thread features must be tapped or milled. These secondary processes greatly reduce the speed advantage of 3D-printed molds.

Size factor: If you're designing skateboards or plastic toolboxes, 3D-printed molds are probably no problem. Parts are limited to 10 cubic inches (164 cubic centimeters), roughly the size of a grapefruit. And despite the high accuracy of current additive equipment, it is still not comparable to machining centers and EDM equipment. The latter typically produces cavity accuracies of ±0.003 inches (0.076 mm) and parts up to 59 cubic inches in volume, roughly six times the volume of 3D printed parts.

High temperature environment: In order to ensure good material flow performance, injection mold needs to be heated to a very high temperature. Aluminum and steel molds are typically subjected to temperatures of 500F(260℃) or higher, especially for high temperature plastics such as PEEK and PEI(Ultem) materials. These metal molds can easily be used to produce thousands of parts and can also be used as transition molds until the final mass production molds are produced. Mold materials manufactured using SLA or similar 3D printing processes are typically photosensitive or thermosetting resins that are cured by UV or laser light. These plastic molds, although relatively hard, break down very quickly in the heat cycle of injection molding. In fact, 3D-printed molds usually fail within 100 uses under mild conditions, such as high-temperature plastics like polyethylene and styrene. For glass filled with polycarbonate and high temperature resistant plastic, only a few parts can be produced.

Compare the cost: One of the primary reasons for using 3D printed molds is the low cost. Production grade machined molds typically cost $20,000 or more, which means that a $1,000 print mold is comparable. This analogy is unfair, however, because the evaluation of a printed mold copy usually only considers material consumption and does not take into account labor, assembly and installation, jet systems, and hardware. Proto Labsd's aluminum mold, for example, costs $1,500 and can be used in production. If you need to produce more parts? With 3D printing molds, you need to reprint and assemble new molds for every 50-100 units you produce. On the other hand, regardless of the plastic used, aluminum molds usually remain in good service after producing 10,000 parts.

Product Design: The principles and practices of traditional injection mold manufacturing have been well studied by the industry for more than a century. 3D printing molds are very new. For example, the die Angle must be greater than or equal to 5 degrees to meet the requirements of most aluminum die. Plastic molds Injection molding of plastic parts is a challenge, the number of plastic mold thimbles and installation positions need to be extra careful.

Plastic moulds (especially high injection temperatures) are somewhat more flexible in terms of increasing cavity wall thickness and reducing pressure. Gate design is also different, tunnel type and point gate should be avoided. Direct gate, fan gate and wing gate should be increased to 3 times the normal size.

The polymer flow direction in the printed mold should be consistent with the 3D printing line to avoid viscosity and high filling caused by low pressure. The cooling system improves the life of the mold to some extent, but does not significantly reduce the number of cycles of the printed mold, because plastic molds do not dissipate heat as well as aluminum or steel molds.

timing

Despite the advantages of fast aluminum molds, there are situations where 3D-printed molds can still be useful. For those who have 3D printers and enough time to explore how printed molds work on injection molding machines, perhaps they think they should just print the molds.

Of course, mold designers must understand how to make functional mold, mold redesign and production will cost a lot of costs. Relevant technical personnel and equipment are also necessary -- mold sandblasting machine workers, thimble installation, injection molding machine operators, etc., because the setting of these parameters is very different from the traditional mold.

But wait -- why not DMLS? Why not just print the metal mold? DMLS uses lasers and precision optics to "paint" parts layer by layer on a bed of fine metal powder, producing fully dense commercial products widely used in aviation and medicine. Some predict that in the future, aluminum and die steel molds may be printed directly, providing ultra-efficient form-following cooling channels that will significantly reduce injection time and extend die life. In some ways, DMLS are slow and expensive to print molds directly, and are usually used only for very small, complex molds, or for machining mold inserts that are difficult to make through traditional machining methods.

Reliable measurement

In general, Harbin 3D believes it is better to use DMLS, SLAs or other 3D printing processes to do what they do well: print parts rather than molds. However, 3D printing injection moulds can be a reliable alternative if the following conditions are met.

1) For small batch and relatively simple parts, the product needs relatively large drawing Angle.

2) Tool and mold design team should be familiar with the design principles of 3D printing mold.

3) There are personnel and equipment for processing and assembling plastic molds.

Final design considerations. If you need the mold to last for a long time, the next step is to use a more reliable material once the 3D printing mold has proven its design. Because plastic molds are mainly produced and used in small batches, some manufacturers have not set up their own 3D printing workshop considering the cost or haven't come into contact with 3D printing models. If you have this idea, please contact us. Acme3d will provide you with complete 3D printing model solutions.