Anyone who has designed a part for injection molding has hit the same gap. A printed prototype tells you about shape and fit. It tells you very little about how the part behaves once it is shot in the real thermoplastic, with real knit lines, real shrink, and the stiffness or flex of the production material. At Formnext 2026, iAM Marketplace plans to show one way across that gap: it will run live polypropylene injection molding through 3D-printed resin inserts, using Forward AM's Ultracur3D RG 3280 on a benchtop APSX-PIM V3 machine.
The demo is not a new concept. Printed soft tooling has been around for years. What makes this one worth a look is the material set and a case study with concrete numbers behind it, which is more than most printed-tooling pitches offer.
The Setup in Frankfurt
According to iAM Marketplace's Formnext 2026 page, the company will be in Hall 12.1 at Booth D61 for the show's November 17–20 run. The stand covers approximately 200 square metres and is split into eight use-case islands: molding, UAVs, sporting goods, dental, orthotics and prosthetics, medical, industrial automation, and filament innovations. The brands in its portfolio include Forward AM, Keystone, iSQUARED, ALTANA Cubic Ink, and Arkema.
The molding island is the hands-on part. iAM lists planned live injection-molding demos at 11:00 and 14:00 each day, November 17–20, on the APSX-PIM V3, with a note that the schedule is subject to final on-site confirmation. The parts will be polypropylene, and the tooling will be printed. 3D Printing Industry reports that the company validated Formlabs Form 4 profiles for RG 3280 and xMOLD, and that the show setup is planned around that Form 4 arrangement, while the earlier industrial case study used Nexa3D printing equipment. iAM estimates 48 to 72 hours from CAD to molded parts, depending on complexity.
Two Resins, Two Jobs
The demo puts two quite different tooling ideas side by side.
Ultracur3D RG 3280 is the reusable-insert material. iAM describes it as a ceramic-filled, high-stiffness resin made for heat-resistant, rigid mold inserts and repeated molding trials, when mechanical demolding is possible. Think of it as the printed stand-in for a machined cavity: you print the insert, wash and post-cure it, and mold parts with it until the design changes or the insert gives out. According to 3D Printing Industry, RG 3280 can also form part of a conventional two-half tool.
xMOLD is the opposite approach. It is a sacrificial resin. The printed mold is removed chemically after molding, so each sacrificial section is intended for a single molding operation. That sounds wasteful until you think about geometry. Undercuts and negative drafts are where conventional tooling gets complicated, because the part has to be released mechanically from a rigid mold. A mold that you dissolve off the part sidesteps that demolding problem, at the cost of printing a new mold for every shot.
The dissolving step takes real time. 3D Printing Industry cites the xMOLD user guide, which describes dissolution in a 1 mol/L sodium hydroxide solution at 70°C. In a test using 30 mm cubes, heated agitation produced 80% dissolution after 16 hours and 97% after 24 hours. Those figures describe test specimens, not a guaranteed release time for your part, and the injected polymer has to be compatible with the removal process too.
Together the two cover a useful range. RG 3280 is for running short series of a design you can pull straight from the tool. xMOLD is for parts whose geometry is difficult to release from a rigid tool. iAM also outlines a combined arrangement, with RG 3280 forming a two-half tool and smaller xMOLD inserts handling features such as undercuts or threads, though it has not yet established how the rigid sections hold up after exposure to the dissolution process.
How Many Shots, Really?
The question every machinist will ask is how long a printed insert lasts. The most useful answer here comes from Forward AM's injection-molding processing guide, as cited by 3D Printing Industry. Under the reported conditions, it lists 1,000 shots for unfilled ABS, POM and PC, and 100 shots for glass-filled PP GF30 and PA 6.6 GF25.
That is a tenfold drop between unfilled and glass-filled materials. For anyone planning a test run, it means the plastic you choose affects the tooling budget as much as the tooling does. The article also notes that performance depends on tool design and molding conditions as well as the resin, and that the guide stresses supporting the printed inserts, cooling them and demolding carefully. Printing a cavity is only one stage in producing a working tool.
iAM is also open about the limits. The company says smaller parts are generally the best fit for printed inserts, and that larger parts needing higher injection pressures and clamping forces, or substantially greater quantities, may favour aluminium or steel tooling. That is a reasonable position. Printed inserts are a bridge between a prototype and production, not a replacement for hard tooling.
The MD ELEKTRONIK Numbers
The strongest evidence for the process is a Forward AM case study with MD ELEKTRONIK, an automotive supplier of data-transmission cables. MD ELEKTRONIK worked with Forward AM and ProductionToGo to make RG 3280 mold inserts on Nexa3D LCD printers for prototype overmolding, with functional electronics and contacts included in the parts.
The problem it was solving is a familiar one. According to the case study, simulations often failed to accurately predict how flexible overmolded parts would behave. The reported results:
- Production time fell from 6–10 weeks to 3–4 days.
- Eight mold components could be printed in 2 hours.
- Cost savings exceeded 5,000 euros in production overheads.
- More than 60 molded parts were produced in 90 minutes, with the mold inserts showing little or no wear.
3D Printing Industry adds a caveat worth keeping: that describes the reported run, and it does not establish the tooling's full service life.
Overmolding flexible material onto cable assemblies is the kind of job where software models can fall short, because the part's behaviour depends on the material, the bond, and the geometry all at once. When a simulation can't give you a trustworthy answer, the quickest route is to mold the part and test it. MD ELEKTRONIK's Markus Kaaserer said the approach let the company check product geometry and discover potential failures before investing in an expensive mold, reducing the number of correction and optimization cycles on the steel tool.
What It Means for Makers
Most readers will not be buying an industrial overmolding cell. The practical lessons still carry over, and a Form 4 is a desktop resin printer of the kind many small shops can reach. The workflow, as iAM describes it, is printing, washing and post-curing the inserts before molding.
Test in the real plastic before cutting metal. iAM points to flexural behavior, snap-fit fatigue and sealing performance as things a directly printed prototype may not represent well. If your product depends on those, a few dozen polypropylene shots from a printed insert can answer questions a resin print cannot.
Match the tooling to the material. The shot-life guidance makes the trade-off clear. Unfilled thermoplastics such as ABS, POM and PC give a longer run for fit checks and small pilot batches. Glass-filled grades will use up inserts quickly, so plan on reprinting them.
Keep parts small. iAM's own advice is that printed inserts suit smaller components. Large cavities and high clamp loads still point toward aluminium or steel.
Consider dissolvable molds for difficult geometry. If a part has an undercut that would otherwise complicate demolding, a sacrificial printed mold might let you mold a handful of samples without redesigning the part, provided you can budget the dissolution time and your polymer tolerates the bath.
Bottom Line
The Formnext demo shows on the show floor what the MD ELEKTRONIK case already reported in numbers: for small parts and short runs, a ceramic-filled printed insert can get production-material samples into your hands in days. It won't replace steel, and iAM does not claim it will. For anyone stuck between a printed prototype and a production tool, it is a practical middle step.
