In Birmingham, UK in September, AddiFab pitched this to hordes of visitors who, at times, waited up to 20 minutes to learn about FIM. Talking to TCT - just the ten-minute wait for us - Staal revealed the motivation behind the company’s cross over between additive manufacturing and injection moulding.

Acetal has previously been used in injection-molded fuel tanks, but material suppliers have now developed new rotomolding grades that incorporate additive packages that raise the heat performance.

These moulds are then placed in an injection moulding machine – AddiFab exhibited alongside a Babyplast system at TCT Show – where a material will be pressed into the mould’s cavity. The mould is then dissolved, inlets and outlets trimmed away, and the final part revealed. Because AddiFab only expects the printed moulds to last one shot, the company says it can process thousands of high-performance injection moulding materials – from flame retardant ABS grades to ultra-soft TPEs to carbon- reinforced PPA injection moulded at 350°C – and enable users to validate their components before scaling to thousands of parts with the same material and the same technology.

Polyamide (PA) 6 has historically been the only material option to achieve a permeation barrier with a single-layer rotomolding process. However, PA 6 is difficult to rotomold and yields a high scrap rate and poor cosmetic appearance. In comparison, acetal delivers a single-layer structure that achieves permeation requirements and provides good processability, low scrap rates, and favorable cosmetics.

Stephen has been with PlasticsToday and its preceding publications Modern Plastics and Injection Molding since 1992, throughout this time based in the Asia Pacific region, including stints in Japan, Australia, and his current location Singapore. His current beat focuses on automotive. Stephen is an avid folding bicycle rider, often taking his bike on overseas business trips, and a proud dachshund owner.

Mitsubishi Chemical sees FIM as a possible gateway into the additive space, having users of FIM process o  the shelf injection mouldable materials to produce prototypes, and perhaps draw conclusions as to the demand that way. That, AddiFab told TCT, is a main goal of the collaboration – and its general industrialisation efforts – but beyond, conversations are still to be had about how the partnership moves forward.

Walk the floor at an additive manufacturing trade show and one will find companies pitching their solutions for the design and prototyping of a product, the manufacture and measurement of the parts, and everything in between.

What happens in between often requires a lot of thought, even more action, and more time than anybody would like to spend. It’s likely that prototypes are 3D printed in one material and the subsequent end-use components injection moulded or machined in another.

While AddiFab is looking to meet the accuracy, repeatability and materials standards of the injection moulding space, it also hopes FIM can bring change to the sector. A big driver for the commercialisation of FIM was to help companies produce small volumes in the early days of product development to test the water. Typically, companies have to meet a minimum order quantity to injection mould parts but, prior to launch, will often be uncertain of the level of demand in the marketplace.

Robomold’s computer-controlled technology allows for precise control of multiple heating and cooling zones, customized material flow, optimized material use, increased product quality, and part traceability. It also offers instant cycle data collection, reduced cycle times, focused cycles for highly engineered resins, and the elimination of labor-intensive processes.

AddiFab believes FIM has the capacity to resolve this issue and encourages manufacturers to work backwards from how they intend to manufacture their part in order to decide how to prototype it.

“Mitsubishi Chemical has aligned now with Freeform Injection Molding as a platform, it has a clear need we have demonstrated we can meet, but I’m not sure either Mitsubishi or AddiFab know where the collaboration is going to end up in a couple of years,” Staal finished. “We can see some evident opportunities with the KyronMAX, Tefabloc, Trexprene and DIAKON series of materials – materials which are difficult to 3D print. But I think Mitsubishi Chemical has about 450  subsidiaries. I haven’t even started talking to ten of them yet. It’s going to be a very interesting journey.”

“We’ve tried to create a platform that combines the benefits from 3D printing with injection moulding, so you get the same low start-up costs, short lead times and design freedom, but the baseline is injection moulding. That means we can process all the materials that an injection moulding user would normally want to process: all those pre-qualified grades for the automotive industries, all the pre-qualified grades for the aerospace industries, the stuff you use for medical devices, which also have to be biocompatible. Most of those materials are not available as 3D printable materials, but FIM allows us to process them off the shelf.”

Gemstar has commercialized several EPA-certified acetal fuel tanks made with its unique Robomold robotic rotomolding process as a fluorination-free solution. “Our innovative technology is a highly viable option that can fill the emerging needs of OEMs and molders who are struggling to fill production needs amidst disrupted supply chains,” said Kevin Lumberg, channel manager for Gemstar Manufacturing.

“Because of minimum order quantity, a lot of products get scrapped,” Staal said. “With Freeform Injection Molding, we don’t have a minimum order quantity. That means [users] can move into the market incrementally. When you hit the tipping point where you can see that it now makes sense to invest in a tool, you can make that investment because your demand is there. You can step away from Freeform Injection Molding into conventional injection moulding, but you haven’t over-invested in capacity from the beginning and you can do the capacity investment when demand has been verified. That means you save a lot of material and you save a lot of energy in the start-up of a new product.”

EPA ruling banning fluorinated barrier layers opens up the acetal option developed and commercialized by Gemstar Manufacturing.

AddiFab is a company positioning itself in the in-between, hoping to relieve manufactures of the above considerations: “I see a gap between the prototyping and production that is not really being remedied by many 3D printing solutions,” Stall emphasised. The company has brought to market Freeform Injection Molding (FIM) and a portfolio of open digital light processing (DLP) 3D printers promising high precision and high repeatability for the additive manufacture of advanced single-use moulds with proprietary tooling resins.

Robomold also delivers a range of sustainability advantages compared to conventional rotational molding. Robotic rotational molding reduces cycle times by 25 to 30% with little to no scrap compared to traditional rotomolding. Researchers at Queens University Belfast recently reported that Robomold’s electrical mold heating method takes significantly less time to heat the mold compared with a conventional oven, saving more than nine minutes (22%) with no appreciable difference in part quality.

“If I want to be able to scale into the millions, then I want to start with injection moulding from day one. The decision point is not, 'do I want to prototype on a 3D printer?' It's, 'what is my end production going to be? Is it going to be a highly specialised geometry or is it going to be a high run of product?’ If it’s high run, let’s start with injection moulding from day one. That’s why we’ve built this platform and that’s why we want to be able to comply with the requirements of the injection moulding industry.”

Rotomolded fuel tanks made of acetal, produced via Gemstar Manufacturing’s Robomold robotic rotomolding technology, have been identified as a highly viable alternative to fluorinated fuel tanks in the wake of an Environmental Protection Agency (EPA) decision to halt the production of fluorinated coatings for high-density polyethylene (HDPE) containers due to per- and polyfluoroalkyl substance (PFAS) contamination.

Similar tentativeness in launching products into market can be found at Mitsubishi Chemical, who recently invested in AddiFab as their partnership intensified. The company would quite like to make around 7,500 of its materials available in the additive manufacturing space, but with further hardware and process developments still needed, Mitsubishi can’t place an accurate measure on demand for many of its products. Without a guarantee of demand, the company is reluctant to invest in the required conversion processes.

“If you’re basing your prototyping on 3D printing, you may get to a point where you get it qualified, then you need to decide how to produce. If you want to scale up to massive levels, you need to go into injection moulding because 3D printing is neither cost competitive nor quality competitive for higher volumes,” Staal argued. “If you decide ‘I’m only going to sell this [product] in low volumes’, then stay with 3D printing, but you need to make that decision before you go into market. That’s a pretty important decision to make.

Gemstar’s exclusive Robomold technology reportedly provides tighter tolerance control with precision-distributed heat and material control for consistent part repeatability and optimized strength-to-weight ratios. It is also said to allow for unsurpassed design flexibility, including the ability to layer different compounds and coatings into finished parts. Rotomolded acetal fuel tanks provide single-layer barrier protection that meets EPA requirements in comparison to injection-molded HDPE tanks that require fluorination.

As end-use requirements become more stringent, Robomold robotic rotational molding is also finding greater use in custom applications. It is reportedly ideal for military, OEM, industrial, and commercial applications, where precision and unsurpassed repeatability are required.

These materials are the kind to feature on approved lists inside factories in the aerospace, automotive, and medical industries. There are similar documents at Danfoss, a company currently testing FIM, which include grades such as PEEK and 40% glass-filled PPS, the former of which is notoriously not the easiest to 3D print, and the latter of which is barely 3D printable at all. It means that Danfoss is rarely able to 3D print prototypes of parts in the same materials it intends to use when it steps into production.

The core of the technology is a six-axis robot that delivers a greater degree of rotation than traditional rotational molding. Instead of using a heating oven, the robot tumbles the electrically heated mold, which incorporates a multitude of separate heating zones. Direct heat applied to these zones enables resin to reach its ideal processing temperature and permits manufacturers to create geometries that were previously unattainable.

"That is a risky process because it entails new validations, it entails new materials, it entails extra time, extra costs,” Lasse G Staal, Co-founder and CEO of AddiFab, said for possibly the umpteenth time on the third afternoon of TCT Show.