An SPI A-1 Diamond Finish is a specialty of Bales Mold Service. We use it to produce the finest finish on molds, producing highly visible or lens quality parts. The SPI A-2 is the most widely used diamond finish, providing good release and good visual parts. An SPI A-3 is a fine choice for release where a high gloss appearance is not required. All diamond finishes work well with chrome and nickel.
Paper Finishes, SPI B-1 to B-3 – Next to diamond polishing, paper finishes are the second most refined finishes available. Paper finishes produce a slightly reflective or glossy shine and very good release. They are often recommended for products that do not require a big decorative or visual impact.
Stone Finishes, SPI C-1 to C-3 – The most economical finish, stone finishes are also the first step in the process of creating both the paper and diamond finishes. Stone finishes provide good release but very little gloss to the plastic part. This is a good choice for strictly functional molded parts where aesthetics are of no importance.
Blast Finishes, SPI D-1 to D-3 – When done properly, blasted finishes can produce some of the most interesting stipples and textures on mold surfaces. From a fine satin texture with varied degrees of gloss to a flat, no-gloss coarse stipple, Bales has the blast media to produce the proper finish for you. Blast finishes are also an excellent way to camouflage weld repairs and slight imperfections.
Types of
Finishes Current SPI
Finish Numbers Description and
Previous Finish Numbers Roughness Comparison R.A.
Diamond #3 Diamond Buff A1 is comparable to #1 0-1
#6 Diamond Buff A2 is slightly finer than 1-2
#15 Diamond Buff A3 has more imperfections than #2 2-3
Paper 600 Grit B1 is finer than 2-3
400 Grit B2 is slightly finer than #3 4-5
320 Grit B3 is comparable to 9-10
Stone 600 Stone C1 is finer than 10-12
400 Stone C2 is slightly finer than #4 25-28
320 Stone C3 is comparable to 38-42
Dry Blasted #11 Glass Bead D1 is finer than 10-12
240 Aluminum Oxide Blast D2 is comparable to #5 26-32
#24 Aluminum Oxide Blast D3 is a little more coarse than 190-230
SPI Finish A-1 -- Grade #3, 6000 Grit Diamond Buff
SPI Finish A-2 -- Grade #6, 3000 Grit Diamond Buff
SPI Finish A-3 -- Grade #15, 1200 Grit Diamond Buff
SPI Finish B-1 -- 600 Grit Paper
SPI Finish B-2 -- 400 Grit Paper
SPI Finish B-3 -- 320 Grit Paper
SPI Finish C-1 -- 600 Grit Stone
SPI Finish C-2 -- 400 Grit Stone
SPI Finish C-3 -- 320 Grit Stone
SPI Finish D-1 -- 600 Stone Prior to Dry Blast Glass Bead #11
SPI Finish D-2 -- 400 Stone Prior to Dry Blast #240 Oxide
SPI Finish D-3 -- 320 Stone Prior to Dry Blast #24 Oxide
SPE -- The Society of Plastic Engineers
SPI -- The Society of the Plastic Industry
SPI(A1) Ra0.005 S136 54HRC 光洁度非常高,镜面效果
SPI(A2) Ra0.01 DF-2 58HRC 光洁度较低,没有砂纸纹
SPI(A3) Ra0.02 S136 300HB 光洁度更低一级,但没有砂纸纹
SPI(B1) Ra0.05 没有光亮度,有轻微3000#砂纸纹
SPI(B2) Ra0.1 没有光亮度,有轻微2000#砂纸纹
SPI(B3) Ra0.2 没有光亮度,有轻微1000#砂纸纹
不辨加工痕迹的方向