Tooling and mold design is a complex process that combines the skills of various experts like tooling engineers, mold designers, material engineers, manufacturing experts, quality check experts, lab technicians, etc.
Following are the key steps involved in tooling:
Feasibility
This is the stage in which the design and tooling team works together to determine the mold materials to be used, functionality, product design specifications, operational issues, need for enhancements, etc.
The feasibility stage involves looking at any potential issues that may come as a result of the geometry of the design. Additionally, aspects like special tooling and mold design requirements are considered at this stage.
Further, engineering teams work together to understand the physical and chemical properties of the selected plastic resins in order to select the mold material and review aspects like mold design, mold flow evaluation, gate location, and cooling conditions.
Finally, tooling specifications are finalized to purchase the required components.
Design
Designs are created in 2D and 3D to give an accurate idea of the mold geometry and sizes. Final designs are created once the preliminary designs are reviewed and approved.
Final designs are created using a tool builder. Specifications are fed into the tool designer to create a mold after final adjustments have been made.
Constructing Primary and Secondary Tools
Tool drawings are prepared along with a review of the construction standards. Once the drawings are verified at all engineering levels and specifications fed into the tool builder, its progress is closely reviewed until mold completion. Completed molds are then inspected for final approvals.
Using the tool for preparing samples
Once the molding process and the parameters are established, the initial samples are produced. These are prepared using defined molding practices. Sample parts are then sent for a final check and qualification.
Final tool corrections
Upon inspection of the sample produced, new adjustments can be recommended for the tools. If the samples are approved, tool construction is verified and documented to be used for future productions. Plastic parts are created using these tools and submitted to the customer for approval before starting the final large scale production process
Tooling is the backbone of plastic injection molding. Without a proper tool design, your plastic part would never scale up properly. A quality tool design can save you enormous amounts of time and money during production. Before you contact a toolmaker, here are a few facts about tooling you should keep in mind.
What is tooling?
Tooling, also known as a mold, refers to the negative cavity space where molten plastic resin is injected to create a part. High quantity and quality parts require proper tooling. Since tool design and construction are complex, fabrication requires significant capital investment and enough lead time to create an effective tool.
Prototype tooling and prototype tools
The tooling design process starts out in the prototype development phase. Here 3D printing, cast urethane, and machining techniques create prototype tools. These low-volume prototypes troubleshoot, develop, and validate the tooling design during pilot production. While this step may seem unnecessary, cutting down on errors in the manufacturing and assembly process early can significantly decrease time and cost later.
Considerations when designing a tool
Proper tooling design and choices need to accommodate for complexity, lifetime, application, and potential production volume of the tool. Choosing which tooling to invest in is the hardest part of the tooling process. If the part is going straight into high volume contract manufacturing, then it will be most cost-beneficial to invest directly into expensive production tooling for the long term. In other cases, such as low volume manufacturing, using a prototype tool may be more beneficial until production increases significantly.
Toolmakers provide necessary assistance with the tool design process because they are well-versed in fabricating techniques and tooling design. They can run mold flow analyses to optimize the tooling design and choose the best locations for parting lines, gate, and ejection locations. A quality prototype design engineer will work closely with toolmakers to ensure the fabrication of the optimal tool for your application.
How to design and make a tool
After collaborating with the toolmakers on the design, the part is ready and approved for the T1 sampling stage. They will build the first tool with a 2-16-week lead time dependent on design considerations. T1 sampling demonstrates that the tooling functions correctly and produces ideal parts. After the T1 sampling is accepted, any necessary modifications and aesthetic mold texturing can begin. These additional modifications can take 1-2 weeks to complete. The modified molds, referred to as T2 samples, are sent for approval of texture and appearance. Once the T2 samples are approved, the toolmaker releases them to the contract manufacturer.
Once with the manufacturer, the T2 samples are placed into the production line for process development and part qualification. The tooling undergoes a series of molding studies that help outline the optimal conditions and characteristics for creating parts using that tool. The manufacturer runs experiment trials to isolate process inputs and corresponding impacts on part characteristics. This initial testing helps the molder validate an ideal processing window that produces parts within specification.
After initial process development, qualifications, and validations, the tool enters a regular production maintenance schedule. Here the tool is regularly monitored for wear and other potential issues affecting part quality or tooling lifetime.
Basic features of a tool
Cavity half – The cavity half is the side of a tool that does not move. It is typically attached to the side of the molding machine.
Core half – The side of the tool that opens and closes with the mold machine against the cavity half. It opens when removing the part from the tool.
Cooling lines – Channels that allow coolant to flow throughout the tool and control the cooling of the plastic part.
Ejector system – Pins on the core half of the tool that helps push the cooled part out after molding.
Runner – A flow path for the plastic resin allowing the press to inject material directly into the part cavity.
Side actions – Moving pieces within the part cavity added to allow for undercuts.
The entire process from prototype to production can take months and significant investment to properly complete. Therefore it is vital to design your parts for manufacturing throughout product development. A product design prototyped using machining, or 3d printing, may not easily translate to a tooling design for high volume production. We recommend partnering with a product development company intimately familiar with the tooling design and the manufacturing process that will initially incorporate that knowledge into designing your product. If you are unsure how to get started or would like some expert advice on designing your tools, contact us and we would be happy to help.
The design of injection molding tools plays a crucial role in determining the success and efficiency of the manufacturing process. Several key factors influence tooling design decisions for plastic parts.
Part Geometry and Complexity
The complexity of the part geometry directly impacts injection mold tooling design. Intricate shapes, undercuts, and fine details may require more complex molds with multiple moving components or specialized features. Additionally, part size, wall thickness, and surface finish requirements must be carefully considered to ensure proper mold design and functionality.
Material Selection and Compatibility
The choice of material for both the part and the mold influences tooling design. Different thermoplastics have varying flow properties, shrink rates, and thermal characteristics that must be taken into account during mold design. Compatibility between the mold material and the injected resin is essential to prevent issues such as warping, sticking, or bad chemical reactions.
Production Volume and Cost Considerations
For low-volume production runs, simpler tooling designs may be sufficient to meet demand while minimizing upfront costs. Conversely, high-volume production requires durable, high-performance molds capable of withstanding continuous use over extended periods.
Surface Finish Requirements
Smooth, polished surfaces may require additional finishing operations or specialized mold coatings to achieve the desired aesthetic appearance of the part. Textured or patterned surfaces may require textured inserts or mold cavities during tooling fabrication.
Tolerance and Dimensional Accuracy
Meeting tight tolerances and dimensional accuracy specifications is critical in many injection molding applications, particularly in industries such as aerospace, automotive, and medical devices. Tooling design must account for factors such as shrinkage, thermal expansion, and part distortion during cooling to ensure precision.
Injection molding is a manufacturing process that uses a metal mold to shape molten plastic resins. The mold is often referred to as tooling. Mold and tooling are relatively interchangeable terms for the metal mold at the heart of the injection molding process. Mold tooling may also be used to describe the process of machining the mold out of a block of metal. A core & cavity is cut into the negative shape of the part. The injection molding machines holds the mold together while it is injected with molten plastic at high pressure. Once the plastic has cooled, the mold is opened and the part is ejected. The process is repeated until the desired amount of parts has been completed. Injection molding is a cost efficient way to manufacture a high volume of complex plastic parts.
Steel and aluminum are the most common metals used to produce injection molding tooling. we prefer to use steel tooling for full-scale, high-volume production. Steel can tolerate higher temperatures and pressure without compromising the mold. Injection mold tooling made from steel can produce hundreds of thousands up to millions of plastic parts. Aluminum mold tooling will typical only produce in the thousands. Steel mold tooling is easier to maintain, will last without rusting, provides an excellent finish to each piece, and is easy to change with simple welding. Steel mold tooling can be made with electrical discharge machining (EDM). EDM is a very precise method and affords our engineers the opportunity to create tooling with highly complex geometry and very tight tolerances that could not be manufactured by conventional means. Aluminum mold tooling is not compatible with EDM and must be made with conventional methods like CNC machining. The high upfront costs should be weighed against the overall advantages of steel mold tooling. Steel molds can be less expensive as they will run many more cycles than aluminum molds. Aluminum mold tooling is also difficult to change or repair and must be replaced often.
Injection molding tooling is highly customizable. we can produce injection-molded parts that match your exact specifications. Working in conjunction with our designers as well as our production facility, we can produce custom plastic mold tooling to meet the unique requirements of your project.
Mold tooling includes sourcing and acquiring all of the mold components and machinery necessary for the job including, jigs, gauges, fixtures, and other equipment. These instruments are critical to the success of the part. The efficiency of a mold can be improved as well as the overall quality of the injection-molded part by using the right injection mold tooling. The tooling process will largely dictate the project cost and quality of the end part. High-quality injection molding tooling will be expensive, however, it will ensure high-quality parts and mold tooling with an exceptional lifespan. Mold tooling that is made to last will help cut the overall project cost and significantly reduce the price per part. The more parts that can be made with the mold tooling, the less each part will cost over time.
Injection mold tooling is generally made of steel, aluminum, or alloys. Most mold tooling will consist of two halves, however, some tooling may be more complex with multiple sides or internal components. The components on the inside of the mold may include slides, guides, lifters, pins, bushings, ejectors, and alignment devices. The proper mold material and components must be used with a compatible injection material to ensure the dimensional tolerances are met and mold tooling longevity.