If you’ve read the blogs and comments made by many who follow this industry, you are familiar with the claim that professional grade 3D printers will replace traditional manufacturing technology (CNC-based milling, machining, stamping, and so on), in the production of all parts and products, and thereby disrupt, or destroy, traditional manufacturing and usher in a new era.

It won’t be that way. Show me a more efficient way than traditional manufacturing to produce thousands and hundreds of thousands of the same part for fractions of pennies.

Traditional subtractive machining, with its “waste” and other “flaws” is still the best way to produce large quantities of parts. In addition, it is still the best way to produce certain designs. For example, some commentators look at the capability to print parts whole as reason enough to eliminate assembly altogether. In some design cases, that capability might make a lot of sense. In others, it just won’t work. It might be radical to hear this today, but I’m hearing from service bureaus that sometimes you might want to print a part in pieces rather print whole. Why would you not use one of the great benefits of additive technology? Because doing so is more cost and time efficient.

Even when additive technologies improve their build speeds, cost and time will be the drivers that determine which technology is used to build one or hundreds of thousands of parts.

3D printing /additive manufacturing machines will be an addition to traditional manufacturing technologies. I predict that manufacturing plants will include additive manufacturing along with traditional subtractive and injection molding technologies. As 3D printers acquire the necessary robustness to operate 24/7, we will see more manufacturers adding them to their production mix. In some situations, such as custom parts, 3D printers will produce a part more efficiently than a traditional manufacturing method, and designers will learn to take advantage of this capability. But some parts should not be produced on a 3D printer, especially when you have established technology that offers more benefits.

3D printing technology may need to change to make it more suitable for additive manufacturing. Most of the 3D printing machine designs are still based on the initial function of prototyping. One company, Voxeljet, based in Germany*, has attempted a new idea. It has developed the Voxeljet Concept—a prototype 3D printer with a nearly unlimited printing length because instead of a build tray, it has a build conveyor.

The majority of professional 3D printers print one or more items on a build tray, which are usually manually removed. This method could be termed discrete 3D printing. The Voxeljet Concept, however, could be termed continuous 3D printing. Parts are printed using an inkjet print head that selectively bonds the powder material layer by layer on a conveyor belt. The print head is tilted at a 35-degree angle and delivers a resolution of 600 dpi.

The build space is listed by Voxeljet as 800 mm x 500 mm x “infinity.” Layer thickness ranges from 150 µm to 400 µm. A cool feature of this unit is that it builds and unpacks without interrupting the operation. The main limitation a designer faces when designing for this machine is managing molds with an almost infinite axis.

The Voxeljet concept is an excellent example of thinking differently and of thinking in ways that enable manufacturing with additive printing.

One of the issues all manufacturers and product develops face with additive manufacturing, however, is the fact that the average engineer is not as familiar with 3D printing /additive manufacturing as they are with traditional CNC machining. Based on conversations with several service bureaus, education is very much needed to ensure that engineers understand the strengths and weaknesses of 3D printing to design appropriately for the technology, especially when they are designing for production and not just prototyping.

Engineers will use additive where it makes economic sense to do so. And they will use traditional machining where it makes economic sense as well. 3D printing is less a disruptive technology than a truly additive concept—adding to the capabilities of manufacturing overall.

Leslie Langnau
llangnau@wtwhmedia.com

 

*Voxeljet makes more traditional 3D printing machines, some of which are distributed by 3D Systems.