It is extremely advised that mold designs be obtained before beginning to work on any injection mold. These classes are just for mold requirements and do not assure workmanship in any manner.
Buyers must engage with providers whose craftsmanship standards and dependability are widely established. Mold life cannot be assured due to differences in design requirements and mold circumstances. This guide is designed to provide the estimated cycle times for each type of mold, whilst ignoring the abrasion caused by rust, inadequate maintenance, and inappropriate molding techniques.
SPI Mold Classifications
Classifications of SPI molds span from 101 to 105 molds and injection molding. The classes listed below are suggestions for obtaining quotes before you buy plastic injection molds. Our goal with these categories is to place orders for uniform types of molds. Our goal with these classes is to reduce confusion in the mold quotation system and enhance client satisfaction.
SPI Class 101 Molds
Extremely high volume manufacturing injection tools designed for million-cycle lifetimes. The hardness of the mold foundation should be at least 280 BHN. Molding surfaces (cavities and cores) should be hardened to 48 Rc or above. All additional features, such as slips, heel bars, gibs, wedges, and so on, should be hardened tool steels as well.
Ejection should be controlled. Wear plates are required for slides. Temperature control measures should be included whenever possible in cavities, cores, and slides. Corrosion in the cooling channels reduces cooling efficiency during the life of the mold, lowering component quality and increasing cycle time.
SPI 102 Molds
Extremely high volume manufacturing injection tools designed for million-cycle lifetimes. This mold is identical to Type 101 except that guided ejection, reinforced slide wear panels, plated water lines, and wear plated cavities are not needed. The rest of the extras are entirely optional. This tool is suitable for abrasion and/or near tolerance items and has a medium to high output rate.
SPI Class 103 Molds
Medium-volume manufacturing injection tools with lifespan cycles of little more than 500,000. The hardness of the mold foundation should be at least 165 BHN. Components and cavities must have a BHN of 280 or above. All other options are optional.
SPI Class 104 Molds
Low-volume manufacturing injection tools with lifespan cycles of no more than 100,000. The mold base can be made of either mild steel or aluminum. Components and cavities can be made of aluminum, mild steel, and every other alloy that has been approved. All other options are optional.
SPI Class 105 Molds
Prototype tools are designed to have a lifespan cycle of no more than 500. The mold foundation can be made of cast metal, epoxy, and every other material that is strong enough to manufacture the bare minimum of prototype parts. This tool is solely for testing purposes. The rest of the extras are entirely optional.
SPI Mold Standards
The SPI Mold Categorizations were written and compiled by the United States Society of Plastic Engineers (SPE) who aim to provide a simplified definition of the different thermoplastic injection tools needed for certain manufacturing demands.
These recommendations are meant to be a starting point for future development, either on a project-by-project basis or based on the needs of the client so that they better represent what is expected of a certain tool. The various categories will necessitate variations in tool design, structure, materials, and parts.
General Specifications
- Before the commencement of production, the customer must approve the mold design.
- Except for the prototype, all molds must have appropriate temperature monitoring channels.
- All features should be labeled with alloy types and Rockwell toughness about 0.005 deep whenever possible.
- On the mold, the customer’s identity, part number, and molding number must be steel engraved.
- On the upper part of all molds, eyebolt openings should be installed. There must be above each and one just below the dividing line to allow for mold eradication in halves if necessary.
Class 101 Standards
Designed for exceptionally high output. This is the most expensive tool, and it is manufactured using just the best materials.
- It is necessary to create a detailed tool design.
- Components of the tool construction must have a minimum hardness of 28 Rc.
- Cavities and cores should be reinforced to at least 48 Rc. All additional details must be made of reinforced tool steels as well.
- Expulsion should be controlled.
- Wear panels are required for slides.
- Temperature monitoring measures should be included whenever possible in chambers, cores, and slider cores.
- Rust in the cooling system reduces cooling efficiency during the life of a tool, lowering component quality and increasing cycle time. Plates or inserts with cooling channels should thus be made of corrosive-resistant material or coated to avoid corrosion.
- All tools must have parting line locks.
Class 102 Standards
Medium to high production tool that is ideal for abrasive materials and/or items that require precise tolerances. This is a high-quality, reasonably priced instrument.
- It is necessary to create a detailed tool design.
- Components of the tool construction must have a minimum hardness of 28 Rc.
- Chambers and cores must be toughened to at least 48 Rc. All additional functional elements must be created and heat-treated.
- Temperature monitoring provisions should be placed directly in cavities, cores, and slide cores wherever practical.
- All tools should have parting line locks.
- Depending on the final manufacturing numbers expected, the following components may or may not be necessary. It is suggested that the desired products be declared a definite requirement for quotation reasons.
- Temperature Monitoring Channels that are Corrosive Resistant
- Cavities with Plates
Class 103 Standards
Tool for medium-scale manufacturing.
- It is strongly advised to create a detailed tool design.
- Components of the tool construction must have a minimal toughness of 18 Rc.
- The cavity and cores should have an Rc of 28 or greater.
- The rest of the extras are entirely optional.
Class 104 Standards
A tool with a low output. Only used in restricted quantities, particularly with non-abrasive materials. Price range: low to moderate.
- Tool design is advised.
- Elements of the tool construction might be made of mild steel or aluminum.
- Cavities can be made of aluminum, mild steel, and every other alloy that has been approved.
Class 105 Standards
No more than 500: Prototype only. The tool should be built as cheaply as feasible to create a small number of prototype pieces.
- All of the elements are optional.
Standards Recap
- If at all feasible, Class 101, Class 102, and Class 103 production machines must be built and designed to perform completely automated cycles with automatic suspension. Class 101, Class 102, and Class 103 equipment should be built to handle the automated component extraction method of choice from the mold.
- With the exception of C105, all equipment should have appropriate cooling for temperature regulation.
- If possible, all elements should be labeled with steel type and estimated Rockwell hardness.
- On the upper side of all tools, transport eye bolt holes should be installed. Except for Class 105, transit eye bolt holes must be drilled in all plates.
The Bottom Line
Molders and plastic injection mold makers can construct a mold in several methods, from the quick and inexpensive prototype mold to the very high-quality, long-term production mold. The issue is ensuring that everyone involved is “on the same page” when a mold is cited. As previously stated, the Society of the Plastics Industry has established its “Standard” for mold requirements for this purpose.
Ensure the plastic mold factory and company you acquire these services from do adhere to these standards before purchasing any mold products from them.
