3D Systems VisiJet M3 Procast is a wax-based build material qualified for the ProJet MJP 3600W MultiJet Printing system. The material is jetted as a heated low-viscosity melt and frozen on a planar build bed; a separate melt-away support wax is deposited for overhanging geometry. Manufacturer documentation identifies layer thickness of 16 µm in high-definition mode and 32 µm in high-speed mode for the platform. Because the material is formulated as a 100 % wax pattern material, it enters the lost-wax investment casting workflow directly without post-cure or additional resin burnout. The printed pattern is worked, invested, and melted from the mold in the initial low-temperature segment of the flask burnout cycle. Published product data place the raw material among MJP wax formulations intended specifically for cast part sizes up to the MJP 3600W build envelope of 298 mm × 183 mm × 203 mm; build volume is a property of the printer, not the material.

What Does the Published Mechanical Property Profile Indicate for Green Pattern Handling?

The green pattern is not a structural end-use part; mechanical data nevertheless determine handling damage rates, support removal, and tolerance to automated extraction. Manufacturer-reported typical values for conditioned specimens cast from printed plaques are summarized below. Tensile testing in accordance with ASTM D638-14 gives a reported tensile strength at break of 4.6 MPa and elongation at break of 12 %; the same standard gives a tensile modulus of 170 MPa. Flexural data were obtained under ASTM D790-17 and indicate a flexural strength of 8.0 MPa with a flexural modulus of 210 MPa. Notched Izod impact is reported at 2.7 kJ/m² under ASTM D256-10. Density at 25 °C is listed at 0.88 g/cm³ by ASTM D792-20. Shore D hardness is reported as 62 by ASTM D2240-15. The softening point is 66 °C when tested by ASTM D36-14. Residual ash is <0.02 % by ASTM D482-19. All values are manufacturer-reported typical data, not lot-specific certification limits.

The low tensile modulus of 170 MPa and elongation of 12 % distinguish Procast from rigid castable photopolymers. Thin filigree features can bend appreciably before fracture, but the correspondingly low tensile strength imposes a handling limit: automated extraction pins and air-knife support removal must be set to pressures that do not exceed the local flexural stress in sections thinner than 0.3 mm. The manufacturer does not publish a minimum wall thickness for investment casting; operational limits are geometry-dependent. Unsupported spans, acute fillets, and free-standing prongs are sensitive to breakage during extraction from the build tray if the chamber is not cooled to 20 °C–25 °C before part removal. The notched Izod value of 2.7 kJ/m² is obtained on a standard 3.2 mm specimen; it does not capture the behavior of thin cast sections. For a printed pattern with wall thickness below 0.5 mm, the relevant failure mode is bending-induced surface cracking rather than notched impact. If pattern sections are exposed to air temperatures above 40 °C, the material begins to approach the reported softening point of 66 °C; localized deformation can occur well before global melting.

Burnout ramp-rate limits and ash residue thresholds in flask casting

The critical processing window for VisiJet M3 Procast occurs in the first thermal ramp from ambient to the point of wax elimination. Softening is reported at 66 °C under ASTM D36-14, and the material softens before any significant mass loss; at flask temperatures above 100 °C, the wax melts and drains or oxidizes depending on furnace oxygen supply. Published data for the exact volumetric expansion coefficient of this material are limited. Standard investment casting practice for pattern waxes with softening points between 60 °C and 70 °C uses ramp rates of 2 °C/min to 5 °C/min through the 60 °C–150 °C segment to avoid shell cracking. Forced-air burnout furnaces with programmable ramp controllers are recommended when the flask contains mixed sections thicker than 5 mm, because exothermic wax vapor ignition can produce localized temperature excursions above the programmed setpoint. Residual ash is reported as <0.02 % by ASTM D482-19; this value is below the threshold commonly required for non-precious dental alloys and most ferrous investment casting. Burnout cycles terminating at 750 °C to 850 °C, with a hold of 60 min to 120 min, are typical for gypsum- and phosphate-bonded molds receiving MJP wax patterns; published data for this specific configuration is limited.

The low ash content of <0.02 % does not eliminate the need for a controlled burnout hold. Incomplete removal of wax from blind internal channels can leave carbon-bearing residue that causes gas porosity in the cast metal. Production-scale MJP casting therefore commonly uses a two-stage burnout: a low-temperature melt-out segment from 100 °C to 250 °C at 2 °C/min to 3 °C/min, followed by a high-temperature oxidizing segment to 800 °C with air exchange of at least 4 flask volumes per hour. The first segment reduces shell cracking from rapid wax expansion; the second segment oxidizes residual carbon in the investment. If the furnace has no forced air exchange, the hold at 800 °C may need to be extended to 2 h for blind cavities. Published data for this specific configuration is limited.

Investment in dental casting is commonly performed under vacuum with a phosphate-bonded material mixed at a water/powder ratio of 0.18–0.22; the MJP pattern is sprued with a 3 mm to 5 mm wax sprue and embedded within 10 mm of the investment exterior. The printed pattern surface is smooth enough to reproduce the 16 µm layer step; however, visible layer lines persist on low-angle surfaces and may require light solvent wiping before investment, provided the solvent exposure is limited to less than 30 s and the pattern is allowed to dry at 20 °C–25 °C. Acetone and ketone cleaning must not be used because they attack the wax and reduce feature fidelity. For heavy prongs and stone-setting undercuts, a slow initial ramp of 2 °C/min is preferred if the flask diameter exceeds 100 mm; this reduces the stress gradient across the investment shell.

A comparison with alternative MJP wax materials and non-wax castable resins

Within the 3D Systems MJP material family, VisiJet M3 Procast is positioned against VisiJet M3 Hi-Cast and VisiJet M2 Cast. Manufacturer-reported typical values for Hi-Cast include a tensile strength at break of 8.4 MPa and a flexural modulus of 620 MPa under ASTM D638-14 and ASTM D790-17, respectively, compared with 4.6 MPa and 210 MPa for Procast. The difference is not a quality defect: Procast is formulated for high-detail jewelry patterns that benefit from lower stiffness and greater elongation, whereas Hi-Cast is used when larger industrial patterns require resistance to fracture during automated handling. VisiJet M2 Cast is a separate wax product qualified for the smaller ProJet MJP 2500W platform; its build envelope and head configuration differ from the MJP 3600W, so material performance is not directly transferable. Castable photopolymer resins generally exhibit higher room-temperature tensile strength and less wax-like burnout behavior; their burnout can require a two-stage cycle with oxygen to oxidize methacrylate polymer, whereas Procast is a wax-based material that melts out in the initial low-temperature stage. Published quantitative ash comparisons across suppliers are limited because burnout residue is highly dependent on furnace airflow and investment chemistry.

The material model code is VisiJet M3 Procast; the “M3” designation places it in the ProJet MJP 3600 series material set. It is distinct from VisiJet M3 Proplast, VisiJet M3 X, and VisiJet M3 Black, which are not intended for burnout casting. Only Procast is matched with a melt-away wax support in the MJP 3600W configuration. Castability is therefore defined by the absence of persistent ash, low softening point, and compatibility with standard flask investments rather than by high mechanical strength.

When VisiJet M3 Procast Replaces Tooled Wax Injection in Low-Volume Production

In production environments where tooled wax injection is economically limited by low batch sizes, the MJP wax pattern process eliminates the steel mold and its 4–8 week lead time; the practical shift is from cavity-filling rheology to layer-wise deposition. Process differences are not limited to geometry. Injection wax patterns are isotropic in mechanical properties and can be produced with a gate diameter of 1 mm to 2 mm; MJP patterns exhibit layerwise anisotropy, with z-direction tensile elongation typically lower than xy-direction values in polymer/wax systems of similar composition, although published data for this specific material orientation is limited. This anisotropy does not normally govern casting accuracy, but it does affect support removal and sprue attachment. In tooled wax injection, pattern mass tolerance is controlled by injection pressure and mold temperature; in MJP, mass tolerance is controlled by jetting frequency, head temperature, and build orientation. With a layer thickness of 16 µm, surface deviation relative to CAD is typically dominated by thermal contraction after solidification, not by staircase error. Thin ribs below 0.5 mm in the CAD model are at risk of distortion during support removal if the pattern is not cooled to 18 °C–20 °C before handling. The material is not suitable for long-dwell storage in direct sunlight or near furnace openings because local radiant heating can exceed the softening point of 66 °C.

Patterns are extracted from the build chamber with the support wax still present. In the case of VisiJet M3 Procast, the support material is a lower-melting wax removed at temperatures below the pattern softening point of 66 °C; manufacturer processing guidance for the ProJet MJP 3600W specifies a heated support-removal station with controlled temperature. The pattern is not submerged in heated mineral oil or alcohol. Published data for this specific configuration is limited; production shops validate bath or oven temperature against section thickness because thin filigree below 0.3 mm can distort when the removal temperature approaches the pattern softening point and the soak exceeds 20 min. After removal, residual support wax is removed by a brief solvent rinse compatible with the material. Air drying at 20 °C–25 °C and 40 %–60 % relative humidity stabilizes pattern dimensions before investing.

Control of jetting viscosity in the MJP 3600W printhead is essential to repeatable pattern mass. Wax-based build materials in this class are typically maintained at printhead temperatures that yield a jetting viscosity of 8 mPa·s to 15 mPa·s; if material is allowed to absorb moisture or if aged containers are not re-homogenized, the drop mass can drift enough to alter local density. Published data for this specific material configuration is limited. Production lines using VisiJet M3 Procast generally place the material container in a conditioned room at 20 °C–25 °C for 24 h before installation and purge the delivery lines to eliminate air entrainment. Batch-to-batch variation in melt point and viscosity is controlled by the manufacturer, but the user-side boundary is moisture exclusion; open containers should not remain uncapped in humid environments above 60 % relative humidity. When jetting faults appear as selective missing lines in thin wall sections, head temperature and support bath temperature are adjusted before part orientation changes are made.

In jewelry casting, the material is used for micro-mounts, filigree, and stone-setting patterns where 16 µm layer resolution preserves prong geometry. The digital workflow accommodates variable pattern thicknesses; but the low tensile strength of 4.6 MPa means that individual prongs below 0.4 mm diameter are frequently supported by an auxiliary wax gate to prevent deformation during investing. In dental casting, patterns for partial frameworks and implant bars are printed and then vacuum-invested; the ash threshold of <0.02 % is relevant to non-precious alloy compatibility. Industrial applications include small pump impellers, orthopaedic instrumentation prototypes, and turbocharger components where internal passages must be formed without ceramic core removal. In each case, the pattern is not machined or injection molded; dimensional accuracy is derived from droplet placement, then compensated for alloy shrinkage in the casting model.

Casting shrinkage compensation for VisiJet M3 Procast patterns is not a material constant. In lost-wax casting, the total linear contraction from CAD to finished casting is the sum of wax thermal contraction, investment expansion, and alloy solidification shrinkage. For common precious metals, CAD scale factors of 1.020 to 1.045 are applied depending on alloy and flask system; manufacturers of MJP wax patterns do not supply a universal scale factor because the investment expansion and alloy cooling rate dominate the result. The function of the pattern is to replicate the scaled CAD geometry with minimal added error. Published data for this specific configuration is limited.

Compared with subtractive machining of wax blanks, the MJP process permits internal undercuts and lattice-like stone seats without tool radius limitations. The material cost is higher than bulk machinable wax, but no chip generation or tool wear occurs. In production-scale precision casting, the choice is often driven by geometry complexity rather than material mechanical strength.

Regulatory compliance information is provided by the material safety data sheet; the wax formulation is not classified as a hazardous mixture under GHS in its supplied form, but local furnace exhaust must be vented because thermal decomposition products can include aldehydes and short-chain hydrocarbons. RoHS compliance applies to the printed pattern only in the pre-cast state; the final metal casting is governed by the alloy specification. Operational boundaries include a maximum continuous air exposure recommended below 40 °C; storage above this temperature can cause pattern distortion, especially in thin sections. The material is incompatible with ketone, acetate, and aromatic solvents. Alcohol wiping must be brief and limited to surface cleaning. Direct exposure to water-based ultrasonic cleaning is generally not recommended because cavitation can erode fine features.