%20203x100.webp)
Vacuum casting
Casting under vacuum, commonly used with polyurethane resins and silicone moulds.
Rapid Prototyping Glossary
V
Definitions for commercial rapid prototyping, production, machining, casting, moulding, finishing and inspection terms.
Vacuum die casting
A die-casting method in which air is evacuated from the die cavity before filling, helping to reduce gas entrapment and porosity.
Vacuum forming
A thermoforming process that uses vacuum to draw hot sheet over a tool.
Vacuum metallising
Depositing a metallic coating in vacuum for decorative or reflective finishes.
Vacuum table
A workholding surface that uses vacuum suction to secure flat sheet or plate materials during machining.
Valve gate
A hot-runner gate controlled by a pin or valve mechanism that opens and closes the melt entry point. Valve gating improves gate cosmetics and can help with sequential filling.
Vapour blasting
A wet blasting process that mixes media with water for gentle cleaning and satin finish.
Vapour smoothing
Refining a thermoplastic surface with controlled solvent vapour.
Vat photopolymerisation
The ASTM additive category covering SLA, DLP, CLIP and related resin-curing processes.
VAT photopolymerization
US spelling of vat photopolymerisation; the additive category covering SLA, DLP and related resin-curing processes.
VDI
Verein Deutscher Ingenieure; the German engineering standard family behind common VDI mould-texture specifications.
VDI 12
A fine VDI mould-texture value, often considered close to a low-polish SPI C-1 style surface.
VDI 15
A fine-to-medium VDI mould-texture value produced for restrained matte tool surfaces.
VDI 18
A VDI texture value associated with a satin finish created through dry-blast glass bead style texturing.
VDI 21
A medium matte VDI mould-texture value associated with dry-blast oxide texturing.
VDI 24
A medium matte VDI mould-texture value rougher than VDI 21.
VDI 27
A relatively coarse matte VDI mould-texture value.
VDI 30
A coarse matte VDI mould-texture value.
VDI 33
A relatively coarse VDI mould texture often cited as visually similar to SPI D-3 and MT-11020.
VDI 36
A coarse VDI mould-texture value used for distinctly matte moulded surfaces.
VDI 39
A very coarse VDI mould-texture value.
VDI 42
An aggressively coarse VDI mould-texture value.
VDI 45
One of the coarsest common VDI mould-texture values.
VDI 3400
A common mould-texture standard family, often produced via EDM, used to specify matte surface textures on injection moulds.
VDI texture
A standardised mould texture designation commonly used in tooling and injection moulding.
Vent depth
The depth of a machined vent in the mould. It must be shallow enough to prevent flash yet deep enough to let trapped gas escape.
Vent land
The short, shallow section of a vent nearest the cavity before the vent opens out to a larger relief channel. Vent-land dimensions are chosen to balance sealing and gas evacuation.
Venting
Providing pathways for trapped air or gas to escape from a mould or process chamber.
Vernier caliper
A hand measuring instrument used for quick dimensional checks.
Vertical machining centre
A machining centre with a vertical spindle orientation.
Vibration finishing
Another term for vibratory or vibrational mass finishing.
Vibratory finishing
Mass finishing in which parts and media move in a vibrating bowl or tub.
Vibratory media tumbler
A finishing machine that deburrs and smooths parts by vibrating them with abrasive or polishing media.
Vice
Also spelled vise in US usage; a mechanical workholding device with jaws used to clamp parts securely on a machine table.
Viscosity
A fluid's resistance to flow, critical in moulding, coating, casting and resin processing.
Vise
US spelling of vice; a clamping workholding device with fixed and moving jaws.
Visual standard
An agreed sample or document that defines acceptable cosmetic appearance.
VMC
Vertical machining centre; a common CNC milling platform in which the spindle points downward towards the worktable.
Void
An unintended empty space inside or on the surface of a part.
Volumetric shrinkage
The reduction in volume that occurs as a material cools, cures or densifies.
Voxel
A volumetric pixel; the smallest addressed volume element in some digital manufacturing and imaging workflows.