What Is a Cube Mold Used For?
Cube molds came out of the packaging industry's obsession with speed. Back in the mid-1990s, Rainer Armbruster at Foboha looked at standard two-shot rotary molds and saw dead time everywhere-waiting for cooling, waiting for ejection, waiting. The cube design solved this by putting four working faces on a central rotating block. While one face injects, another cools, another ejects, and the fourth stands ready. The machine never waits.
The original applications were all packaging. Flip-top closures, two-color caps, hinged lids-anything produced in high enough volumes to justify the tooling investment. A 32-cavity system running 8.5-second cycles can push out over 300,000 pieces per day. That kind of throughput matters when you're supplying consumer goods companies burning through millions of closures per week.
How the Technology Actually Works
The cube sits between two stationary mold halves. Each face carries identical cavity sets. When the mold opens, the cube rotates 90 degrees, presenting fresh cavities to the injection position while moving the just-filled cavities into cooling position. The previous cooling cavities rotate to ejection, where parts drop free. Everything happens at once.
For two-component work, the setup adds a second injection unit-typically positioned above or beside the clamp. First shot goes into one parting line, cube rotates, second shot hits the parts from the opposite side. The substrate and overmold bond while still warm. Most combinations involve PP with TPE, though PC/ABS assemblies and PA with soft-grip materials show up regularly in automotive interiors.
What makes this different from a standard rotary table? Footprint, mostly. Cube molds double your cavity count without spreading wider across the platen. A conventional 16+16 two-shot mold might need a 500-ton machine. The cube equivalent fits on smaller tonnage with room to spare.
Where These Molds Earn Their Ke
Packaging still dominates. The flip-top closure market alone justifies hundreds of cube systems worldwide. Arburg and Foboha demonstrated a 32-cavity two-color flip-top running at K2016 that hit sub-9-second cycles-numbers that standard rotary tools simply cannot match.
But the technology has migrated. BSH Hausgeräte (the appliance division behind Bosch and Siemens) switched their dishwasher roller production to a Reversecube system in 2019. The previous setup used two separate machines plus an assembly line. The cube consolidated everything-injecting the socket, injecting the roller from different material, assembling them in-mold-into one cell. They reported 40% cycle time reduction and 60% floor space savings. Those numbers got attention across manufacturing engineering departments.
Automotive interiors picked up the technology next. Multi-material knobs, buttons with soft-touch surfaces, ventilation components with integrated seals-all candidates for cube production. The medical device sector has started exploring it for syringe plungers and multi-part assemblies where contamination concerns favor in-mold assembly over downstream handling.
Configuration Variants Worth Knowing
Foboha's Reversecube
Foboha's Reversecube splits the cube horizontally into two counter-rotating halves. Each half processes different materials at different temperatures-something impossible in a single-block design. This matters when you're combining PA66 at 280°C with a TPU that degrades above 220°C.
The Double Cube
The Double Cube stacks two synchronized cubes between the platens, creating three parting lines. Output doubles again, though the tooling complexity and maintenance requirements scale accordingly. Most shops treat this as specialty territory.
Compactcube Variants
Compactcube variants strip down the mechanism for lower-volume applications. The cycle time advantages shrink, but the multi-component capability remains. It fits shops that can't justify full cube investment but still need two-shot capability beyond what standard rotary tables deliver.
Economics That Drive Adoption
The question isn't whether cube molds cost more-they do, substantially. A high-cavitation cube tool runs 2-3x the price of an equivalent rotary mold. The question is where payback happens.
At volumes above 20 million parts annually, the math usually works. Cycle time drops 30-40%. Machine hours per part drop proportionally. You're running one cell instead of two. Labor for assembly operations either shrinks or disappears entirely when in-mold assembly replaces downstream work. Energy consumption per part falls because cooling happens during injection rather than adding to cycle time.
The breakeven point shifts depending on part geometry, material costs, and local labor rates. European manufacturers pushed cube adoption earlier than North American shops partly because higher labor costs made the automation premium easier to justify. Chinese toolmakers now build cube molds at price points that have shifted the calculus for mid-volume applications.
Practical Limitations
Cube tooling requires purpose-built machines. You can't drop a cube mold into a standard horizontal press. Arburg, Engel, and KraussMaffei all make cube-capable platforms, but the installed base remains limited compared to conventional equipment. If your shop doesn't already have a cube machine, the mold is only half the investment.
Material combinations face the same compatibility constraints as any two-shot process. Chemical bonding between layers depends on molecular compatibility and processing windows. PP-to-TPE works reliably. PC-to-silicone requires careful temperature management. Some combinations simply don't bond regardless of equipment.
When to Consider Cube Technology
The conversation starts with volume. If your annual requirements don't crack eight figures, standard multi-shot tools probably make more sense. Below that threshold, cube advantages get eaten by amortization on the tooling premium.
Next factor: assembly operations. If your current process involves molding two parts separately and assembling them downstream-especially if that assembly requires precision alignment-in-mold assembly via cube might eliminate that entire operation. The BSH dishwasher roller project succeeded specifically because it replaced a separate assembly line.
Floor space constraints sometimes tip the decision. Running one cube cell versus two conventional machines can free up significant plant real estate, particularly valuable in facilities already at capacity.
Cycle time sensitivity matters most in commodity applications where margins run thin and competitors can win contracts with single-digit cost improvements. If 35% faster cycles translate directly to per-part cost reduction, the cube justifies itself relatively quickly.
Technical Reference: ABIS Mould Engineering
For project inquiries involving cube mold development, contact the engineering team at www.abismould.com. ABIS specializes in multi-component injection mold systems for packaging, consumer products, and technical applications.