• Reduces the chance of damage to the part due to friction during release
• Reduces wear and tear and chances of damage to the mold
• Ensures a uniform, smooth, unscratched finish when required
• Ensures the integrity and uniformity of other surface finishes and textures
• Reduces overall cooling time by lessening or eliminating the need for unconventional ejection setups
• Most, if not all, of these benefits offer either direct or indirect overall production cost reductions

The SPI is that Society of the Plastics Industry  sets standard for plastics industry in the United States that identifies the cosmetic quality of plastics, Upmold uses  the SPI standard to define finish of plastic injection molded parts.
There are twelve grades of finishes specified by the SPI in four categories that range from shiny to dull. Each grade has different requirements for allowable deviation from perfect, with lower numbers allowing for less deviation and higher numbers allowing for more deviation.
Below specifications provide guidelines for mold surface finishes as provided by the UP MOLD.  For more information visit Tooling Manufacturing.

• SPI texture standard
• SPI mold finish standards
• Plastic surface finish chart
• SPI mold finish Guide
• Mold surface finish standards
• SPI Mold finish comparison 
• Injection mold  surface finish standards
• Injection molding surface finish
• Mold surface finish
• SPI surface finish specification
• SPI surface finish chart
• SPI surface finish standards

SPI a1 is comparable to RA.0-1 made by #3 diamond buff
SPI a2 is slightly finer than a1 and RA.1-2 made by #6 diamond buff
SPI a3 has more imperfections than a2 and RA.2-3 made by #15 diamond buff

SPI b1 is finer than a3 and RA.2-3 made by 600 grit
SPI b2 is slightly finer than b1 and RA.4-5 made by 400 grit
SPI b3 is comparable to RA.9-10 made by 320 grit

SPI c1 is finer than b3 and RA.10-12 made by 600 stone
SPI c2 is slightly finer than c1 and RA.25-28 made by 400 stone
SPI c3 is comparable to RA.38-42 made by 320 stone

SPI d1 is finer than c3 and RA.10-12 made by #11 glass bead sandblasting
SPI d2 is comparable to RA.26-32 made by 240 aluminum oxide sandblasting
SPI d3 is a little more coarse than d2 and RA.190-230 made by #24 aluminum oxide sandblasting

Shiny Finishes

SPI-A1, A2, A3

Semi-Gloss Finishes

SPI-B1, B2,B3

Matte to Dull

SPI-D1,D2,D3

Texture

SPI-D1,D2,D3

 Roughness Average -Ra

Ra is the arithmetic average of the absolute values of the profile heights over the evaluation length.

 Ten Point Height of Irregularities – Rz(ISO) 

RZ is the average value of the absolute values of the heights of five highest-profile peaks and the depths of five deepest alleys within the evaluation length.

Surface roughness terminology and parameters

Ra and Rz are different parameters of roughness.

• Ra is the average roughness of a surface.
• Rz is the difference between the tallest “peak” and the deepest “valley” in the surface.

Ra vs Rz is like comparing inches to meters. They are not compatible. Use one or the other not both.

Surface roughness technical data

• EDM Mold Surface
• VDI 3400 Texture
• Surface finish VDI 3400
• VDI texture mold standards
• SPI vs VDI finishes
• Surface roughness comparison chart
• VDI Mini draft angle chart
• VDI 3400 Depth
• Surface roughness conversion

• EDM Mold Surface
• VDI 3400 Texture
• surface finish VDI 3400
• VDI texture mold standards
• VDI surface finish conversion

• EDM surface finish chart
• EDM mold texturing
• EDM mold finish,
• EDM mold surface finish
• EDM surface texture
• EDM surface finish chart
• EDM plastic finish
• EDM surface roughness
• EDM plastic molding
• Surface finish EDM
• VDI surface finish chart
• VDI surface finish
• Charmilles texture
• Charmilles Finish
• Charmilles surface finish chart
• Charmilles EDM surface finish chart
• AGIECHARMILLES EDM surface finish

• DA-PA = Drafting Angle for Polyamide
• DA-PC = Drafting Angle for Polycarbonate
• DA-ABS = Drafting Angle for Acrylonitrile-Butadiene-Styrol
• Glass-reinforced materials require more drafting.

• DA-PA = Drafting Angle for Polyamide
• DA-PC = Drafting Angle for Polycarbonate
• DA-ABS = Drafting Angle for Acrylonitrile-Butadiene-Styrol
• Glass-reinforced materials require more drafting.