The SPI Mold Classifications were developed by the U.S. Society of Plastic Engineers (SPE), with the intent of having a simplified definition of the type of injection tool for thermoplastics required for a set production need.

These guidelines are intended to be just a reference that frequently further evolve, on a project by project basis or depending on the customer so that they better reflect what is required of a specific tool.

The different classifications will dictate differences in tool design, construction, materials, and components.

UPMOLD provides SPI mold classifications from class 101 to 105 molds and Injection molding. We all pledge our best effort to satisfy our customer’s needs regarding their expectations of quality, customer service, value, delivery and innovation.

The following classifications are guidelines to be used in obtaining quotations and placing order for uniform types of molds. It is our desire through these classifications to placing order for uniform types of molds. It is our desire through these classifications to help eliminate confusion in the mold quote system and increase customer satisfaction.

SPI MOLD CLASSIFICATIONS OF INJECTION MOLDS UP TO 400 TONS

Customer is to approve mold design prior to start of construction. All molds are to have adequate channels for temperature control. Wherever feasible, all details should be marked with steel type and Rockwell hardness. Customer name, part number and mold number should be stamped on all molds. All molds and large components should have adequate provisions for handling, i.e., eyebolt holes, prybar slots, etc.

1. Class 101:  Extremely High Volume
   Extremely high volume production injection tools built for lifetime cycles exceeding one million.
2. Class 102: High Volume
   Medium to high volume production injection tools built for lifetime cycles not to exceed one million.
3. Class 103: Medium Volume
   Medium volume production injection tools built for lifetime cycles not to exceed 500,000.
4. Class 104: Low Volume
   Low volume production injection tools built for lifetime cycles not to exceed 100,000.
5. Class 105: Prototype Only
   Prototype only tools are built for lifetime cycles not to exceed 500.

Class 101 Tool – Cycles: One million or more

Description: Built for extremely high production. This is the highest priced tool and is made with only the highest quality materials.

• Detailed tool design required.
• Tool structure components to have a minimum hardness of 28 Rc.
• Cavity and cores must be hardened to a minimum of 48 Rc range. All other details, such as sub-inserts, slides, heel blocks, gibs, wedge blocks, lifters, etc. should also be of hardened tool steels.
• Ejection should be guided.
• Slides must have wear plates.
• Temperature control provisions to be in cavities, cores and slide cores wherever possible.
• Over the life of a tool, corrosion in the cooling channels decreases cooling efficiency thus degrading part quality and increasing cycle time. It is therefore recommended that plates or inserts containing cooling channels be of a corrosive resistant material or treated to prevent corrosion.
• Parting line locks are required on all tools.

Class 102 Tool – Cycles: Not exceeding one million

Description: Medium to high production tool, good for abrasive materials and/or parts requiring close tolerances. This is a high quality, fairly high priced tool.

• Detailed tool design required.
• Tool structure components to have a minimum hardness of 28 Rc.
• Cavities and cores should be hardened to a minimum of 48 Rc range. All other functional details should be made and heat treated.
• Temperature control provisions to be directly in the cavities, cores, and slide cores wherever possible.
• Parting line locks are recommended for all tools.
• The following items may or may not be required depending on the ultimate production quantities anticipated. It is recommended that those items desired be made a firm requirement for quoting purposes.
  • Corrosive Resistant Temperature Control Channels
  • Plated Cavities

Class 103 Tool – Cycles: Under 500,000

Description: Medium production tool.

• Detailed tool design recommended.
• Tool structure components must have a minimum hardness of 18 Rc.
• Cavity and cores must be 28 Rc or higher.
• All other extras are optional.

Class 104 Tool – Cycles: Under 100,000

Description: Low production tool. Used only for limited production preferably with non-abrasive materials. Low to moderate price range.

• Tool design recommended.
• Tool structure components can be of mild steel or aluminum.
• Cavities can be of aluminum, mild steel or any other agreed upon metal.

Class 105 Tool – Cycles: Not exceeding 500

Description: Prototype only. Tool to be constructed in the least expensive manner possible to produce a very limited quantity of prototype parts.

• All components are optional

Notes and Comments:

1. Class 101: Extremely High Volume, Class 102: High Volume and Class 103: Medium Volume production tools, if at all possible, should be designed and manufactured to run fully automatic cycles with automatic ejection.    Class 101, Class 102 and Class 103 tools should be designed to best accommodate the selected method of automated part removal from the mold.
2. All tools, with the exception of C105, should have adequate cooling for temperature control.
3. Wherever feasible, all components should be marked with steel type and Rockwell hardness approximately.
4. All tools should have transport eyebolt holes on the top side. With the exception of Class 105, transit eyebolt holes should be machined in all plates.
5. Customer should approve tool design prior to the start of manufacturin

CLASS 1 UNIT INSERT

1. Detailed mold design required.
2. Insert retainer to be uniform hardness of at least 280 BHN.
3. All molding and/or functional details are to be made of tool steel hardened to at least 48
R/C.
4. Slides must have wear plates.
5. Temperature control provisions to be in cavities, cores and slides wherever possible.
6. Over the life of a mold, corrosion in the cooling channels decreases cooling efficiency
thus degrading part quality and increasing cycle time. It is therefore recommended that
plates or inserts containing cooling channels be of a corrosive resistant material or treated
to prevent corrosion.
7. Parting line locks are required to be on all molds.
8. Insert retainers must have leader pins and bushings or some similar guidance system.

CLASS II UNIT INSERT

1. Detailed mold design recommended.
2. Insert retainer to be uniform hardness of at least 165 BHN.
3. Cavities and cores must be 280 BHN or higher.
4. Water channels to be included.
5. All other extras are optional.

CLASS III UNIT INSERT

Can be constructed from aluminum, cast metal, cast epoxy or any material with sufficient strength
to produce minimum prototype parts.

Important: Refer to the general specifications to complete the details of this section, except for prototype molds.

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