TCT Magazine: How EnvisionTEC Keeps Turning up the Wax in 3D Printing
This article first appeared in TCT Magazine| Europe Edition | Volume 26 | Issue 1
When EnvisionTEC launched its very first 3D printer in 2002, it was developed with the jewellery industry in mind. Along with a requirement for highly detailed castable patterns, EnvisionTEC saw there was a significant opportunity to save time and money for a market that was painstakingly hand carving wax patterns.
In the early days of jewellery 3D printing, EnvisionTEC machines could print smooth, highly detailed patterns that were completely plastic and required professional expertise to cast. While this was sufficient for small pieces under 5 grams of finish weight, anything more substantial would expand so much during burnout that the stress would often fracture the investment.
To overcome this, makers of investments developed extra-high-strength bonds to withstand those pressures, whilst 3D manufacturers simultaneously embarked on the development of formulas containing more wax, which burns off before the plastic to make room for expansion during the burnout.
At EnvisionTEC, the company graduated from its original waxless Plastic Investment Casting material, known as PIC, to Exceptional PIC (EPIC), with 8% liquid wax. Over the years, EnvisionTEC added more and more wax, in both liquid and powder form, for specific purposes, working to preserve print quality. That resulted in EnvisionTEC’s Easy Cast (EC) materials line dedicated to fool-proof casting.
Until last year, the highest wax content was found in the company’s EC3000 material, which contained a 55% blend of powder and liquid wax. Now, coupled with highspeed continuous 3D printing technologies like cDLM (Continuous Digital Light Manufacturing), EnvisionTEC is intent on changing the game for castable materials for the jewellery sector and beyond.
One of the challenges of 3D printing with photopolymer resins that contain wax is the softness of the material. As each layer is printed during the build process, the print is peeled off the build platform before advancing to the next layer, which exerts significant separation force on the object being printed. The softer the material, the more supports are required to withstand this force without tearing.
With cDLM, however, there are almost zero separation forces, as parts are essentially built in free space, which means softer materials with high wax content can be printed with very few supports.
“For jewellers, more wax means easier casting. It’s as easy as that,” explains EnvisionTEC founder and CEO, Al Siblani. “The more plastic or photopolymer content you have, the more fussy and controlled the casting process has to be because the plastic expands so much during the burnout. Wax makes casting easier. Many jewellers learned casting as a craft from their relatives using wax carvings or wax patterns. Casting 3D printed patterns with more plastic content is different than casting a wax piece, so we can bring back that ease to the casting process with more wax.”
EnvisionTEC’s Easy Cast 2.0 C contains about 90% wax content, which is designed to make casting as easy as with wax patterns using standard investments. With the addition of hardeners, EC 2.0 C also produces crisp, accurate details with a smooth surface finish. In concert with cDLM, this new material has also opened the door to 3D printing of entire spruing trees (a collection of wax models assembled in a tree-like formation for lost wax casting) of rings, removing yet another labour intensive part of the casting process.
“The ability to 3D print full spruing trees is going to be a game changer in terms of speeding up and simplifying production for jewellery makers,” Al commented. “Right now, jewellers clean up the patterns after printing and attach them to a spruing tree for casting. It will take time for jewellers to manage the digital process of putting all the rings on a tree, and we’re working to make that easier for them, too.”
These developments will be welcomed by company’s like Birmingham-based Weston Beamor. Back in 2001, the company was the first precious metal casting business in the UK to invest in 3D printing but it wasn’t until it came across EnvisionTEC’s DLP Perfactory series that the company saw the combination of materials, build speed, capacity and most importantly, resolution required for the jewellery market. Now, operating out of the city’s renowned Jewellery Quarter, it houses two EnvisionTEC P4 machines, one running
EC3000 for lost wax casting and the other running RC90 to create silicon moulds for multiple castings.
“The advent of CAD software opened up new possibilities for jewellery designers in complexity, speed and accuracy, so 3D printing became increasingly important for jewellery manufacture,” Ed Hole, Head of CAD Design & 3D Printing at Weston Beamor explained. “CAD and 3D printing is now the industry standard production method and, as a result, there has been more and more demand for better castable resins. Simply put the higher the wax content the better it will cast, but resin manufacturers also have to consider build strength and curability, so it’s not an easy balance.
“In our experience EC3000 is the most consistent performing resin for build quality and castability.”
3D printing has helped to transform the jewellery sector to a point where the industry is no longer reliant on skilled wax carvers but rather a mix of traditional and technological skill. Looking to the future, EnvisionTEC believes these strides in casting materials could have implications beyond jewellery into more industrial areas where large investment castings with high accuracy and surface finish details are required.
“The tools and techniques for making jewellery haven’t fundamentally changed in the last thousand years or so – files, hammers, saws etc,” Ed commented. “However, in the last 15 years the industry has seen a revolution in the way pieces are designed and manufactured, all down to 3D printing. Jewellery making has become the perfect marriage of technology and traditional craftsmanship – cutting edge CAD modelling and 3D printing together with skilled artisans.”
With EnvisionTEC’s growing line of cDLM printers — four build sizes are now offered — a new era of castable 3D printing is here.
Al adds: “Progress in 3D printing is rarely about one single printer or technology, or even the functionality of independent materials. Powerful change comes from the interplay of machines and materials, and that’s what makes this sector so challenging and fascinating.”