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3D Printed Injection Molds

Mold the Impossible!

Merging 3D Printing and Injection Molding

Using the new FIM (Freeform Injection Mold) resin RapidMade is revolutionizing low volume manufacturing by printing low cost injection molds overnight. 

Every single injection molding resin in the world is available for the low price and short lead time of 3D printing.

This is a hybrid technology: Instead of 3D printing the final part, we are printing the molds then molding the parts. FIM molding has a few major advantages to 3D printing.

1. Materials: 3D printing processes are complex and it is difficult to qualify materials. Some materials can be molded and cannot be printed. That means the available resins for 3D printing are a tiny fraction of the universe available via injection molding.

2. Mechanical properties: Even the best mechanical 3D printing processes (SLS or MJF) do not yield the isotropic properties of molded parts. The pressure of injection molding creates fully dense parts. Many 3D print processes express poor z layer adhesion or low density, leading to part failure.

3. Finish: DLP resins like the FIM resin are photopolymers made in a liquid vat. This process has the thinnest layers, highest detail and smoothest finish of all 3D printing processes. Textures in the file will translate into the mold. Real thermoplastics with SLA level detail and finish.

Dissolvable molds at scale. Small single use molds can be cost effective.

FIM Process Overview

 The Freeform Injection Molding process begins just like any other 3D printing process – you upload your files and place an order. Although instant quoting is not yet available we are offering manual quoting at this time. We take the responsibility of designing the mold and helping you conform with the best practices of injection molding. We offer thorough design review and documentation standard.

Our advanced tooling composite will last several hundred parts and can handle high heat or abrasive resins like glass-filled nylon or PEEK. If time is of the essence or must violate the rules of molding, tools are completely dissolvable in a lye bath.

Once the mold is printed, we run it on a standard injection molding machine. Currently part size is limited to 4.5″x4.5″x2.5″ – we hope to increase that very soon! Injection molding machines produce dozens of parts per hour and utilize almost every available resin on the market.

After the part cools it is ejected, post processed, quality controlled and shipped out. RapidMade offers many secondary post processes like heat stake inserts, bead blasting and automotive paint.

3D Print

Soluble tools for unlimited design freedom

Inject

Shoot any injection molding material

Dissolve

Dissolve for impossible parts

Available Injection Molding Plastics

Available does not mean in stock and lead times may vary. Specific grades, colors and additives may require an MOQ. RM will only stock basic materials and colors with expected high demand.

Please note that even if materials are 3D printable, injection molding will yield better mechanical properties and surface finish, particularly when compared to filament materials like ABS, PC, PET, PPSF and Ultem. Filament materials exhibit 75% reduced mechanical properties between the Z layers. Molded parts will be 100% isotropic.
PlasticBenefitsApplicationsNotes3D Printable?
ABS (Acrylonitrile Butadiene Styrene)General purpose plastic. Cheap, rigid and dimensionally stable. Very popular plastic for a reason.Cosmetic parts, consumer products, electronics devices For best results follow best practices for injection molding part design. Not suitable for snap fitsYes
POM or Acetal (Polyoxymethylene)Durable, rigid, strong, lubricious, solvent resistant, elastic, low creep, excellent fatigue resistance.Gears, pumps, impellers, conveyor parts, blades and scrapers, food contact surfacesStiff, stable and durable, a staple of automation applications. Low friction and approved for food contact.No
PMMA or Acrylic (Polymethyl Methacrylate)Clear, glossy, scratch-resistant, stable shrinkage. Naturally UV resistant.Light pipes, diffusers, shades, outdoor coversCan be brittle, requires significant draft, poor chemical resistance; printed molds will not have optical clarity, diffused finish similar to SLANo
PC (Polycarbonate)Clear, strong, impact resistant, stable shrinkage, heat resistance, high cosmetic finishes.Lighting, electronics, automotive and aerospace, phone housings, medical devices, safety glass.Top mechanical properties. Poor chemical and UV resistance without additives. Often fire retardant and medical/food grade.Yes
PET (Polyethylene Terephthalate)Good moisture barrier properties, stiff and flexibile, food contact clearBottles (food grade), packaging, clam shells, snap fitsVery poor UV properties and not the highest mechanical strengthYes
PA or Nylon (Polyamide)Balanced stiffness and flex, reinforced options for high strength and temperature tolerance, Chemical resistant.Thin-walled parts, gears, bearings, structural components.Very common material for mechanical applications, high warp potential, hygroscopicYes
HDPE (High-Density Polyethylene)Extremely high impact UV and chemical resistance, high shrink, low dimensional stability, inexpensive. Very low stiffnessOutdoor furniture, containers, toys, gas and other chemical contact applicationsUltimate in chemical resistance. Extremely low cost. Beloved in chemical and food applications. Very easy to clean. High shrinkage makes it hard to control toleranceNo
PP (Polypropylene)Cost-effective, impact resistant, flexible, acid/base resistant, floats. Very low stiffnessLiving hinges, snap fit lids, packaging, medical devicesSimilar to HDPE in stiffness and chemical resistance. Lower Density than HDPE and more flexibile - semi-rigidYes
PPSU (Polyphenylsulfone)High-temperature tolerance, dimensional stability, toughness, sterilizable.Medical instruments, food contact surfaces, sterilization trays, automotive and aircraft parts.Can be difficult to mold, sensitive to organic solvents and hydrocarbons, does not accept color additives wellYes
PEI or Ultem (Polyetherimide)High-temperature, flame retardant, Low toxicity/off gassing, strong, stable, chemically resistant.Medical and chemical instruments, Passenger aerospace, transit and rail (where FST rating a requirement,) HVAC, lighting.Top choice for transit applications - not many materials rated for smoke toxicity. Great mechanical, thermal and chemical propertiesYes
PEEK (Polyether Ether Ketone)High-temperature, flame retardant, strong, stable, chemically resistant. Bearings, pistons, cable insulation, drones and aircraft.Highest standards in mechanical and thermal properties. FST rated. Extremely expensive resin.No
TPU/TPEFamilies of elastomers from shore 5 - 95A; medical and food gradeElectronic insulators and strain relief, seals, gaskets, hoses, grips, end effectorsExtremely high compression, rebound, and stretch properties. Wide range of hardnesses. Chemical and abraison resistantYes
SiliconeWide range of LSR resins with high heat and tear resistance; medical and food gradeprosthetics, gaskets, seals, end effectors, lab equipment, medical devices2 part system requires extra mixing and cure time, highly coveted in many industriesNo
Custom Material / Customer SuppliedGive us your toughest challenges!Special colors, composites and additives. Glass, carbon, aluminum fill. UV resistance, lubrication and other additives. Special grades of listed plastics.Customers can supply materials or pay us to source them.N/A

3D Printed Injection Mold Design Guidelines

Wall thickness: Consistent wall thickness between 0.060″ and 0.200″ will yield the best part quality. Fillet all sharp edges and joints to reduce stress during shrinkage. Concentrated mass causes concentrated contraction and that will warp your parts.

Ribs and Gussets: To avoid thicker walls use ribs for enhancing part strength and stiffness, as they minimize material use and cooling time while maximizing strength. These features improve dimensional stability by stiffening the design. With printed molds, complexity does not add cost! Ideal ribs and gussets are 50- 60% of the wall thickness. Overly thick features cause sink.

Parting line, draft angles and other considerations: Dissolving molds can be expensive – but getting repeat production molds that eject volume parts is not that simple either! For customers who want to reuse their molds we must consider where the mold will separate. Interference, called an undercut, is a feature that prevents removal of a part from a mold. Sometimes a core is necessary to form a cavity inside a part. Generally a half degree of draft and ejector pins are needed to remove the parts. An injection port is always neccesary to shoot the mold. These are design considerations that require up front engineering costs but saves substantial money over hundreds or thousands of parts.

Understanding tolerancing and other limitations: 3D printing is not as accurate as machining, so a printed mold is not as accurate. Milled production molds will be milled between 0.001″ – 0.005″: while printed molds typically hold between 0.010″ – 0.015″. This additional variance will pick up in your parts. Additionally, the molding resin will also shrink. We will adjust for this shrink rate but shrinkage causes additional part variance which limits the tolerances we can offer. For customers with the most demanding drawings post machining is available.

Additionally this is a new process with limited finish options. In-model textures work astoundingly well but customers must supply them. Traditional injection mold tooling companies have a lot of chemical etch finishes that we cannot offer at this time.

Additional technical process information will be available in the near future as it is validated and published.

FIM Video Overview

Start Injection Molding Today!