Prototyping is a critical step in product development that allows companies to perfect their design before bringing products to market. Although testing prototypes can take some time, new prototyping technologies are faster and offer better results in bringing products to market.
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WHAT ARE PROTOTYPES?
Prototypes are representative models created to simulate a product, part, or component. These physical models get produced before beginning the manufacturing process and are a critical step in the development of new products. Prototypes can serve a variety of purposes, depending on the goal of the prototyping phase and the technology used in prototype production. The primary uses of prototypes include the following.
- Proof of Concept: Prototyping allows manufacturers to check the feasibility of a concept or design. Product ideas serve as models for physical samples that then get tested and modified as necessary.
- Design verification: Because it is quick and cost-efficient to create prototypes, prototyping can test multiple design iterations. With prototypes, designers can verify and refine their design as many times as necessary before investing in mass production.
- Product testing: Prototypes can be useful in testing the functionality of a part or product before production. Using prototypes, companies can evaluate failures and mechanical issues of a new product or part. This process can help uncover flaws and complications before they begin manufacturing the actual product.
- Product demonstration: Prototypes can serve as a sample presented to customers for early product demonstrations. Physical prototypes allow customers to better understand a new product, interact with a realistic model of that product, and provide feedback before manufacturing begins.
Building prototypes benefits your business by allowing you to identify errors or problems with products before mass production begins. When you refine and improve your designs through prototyping, the result is a higher quality and more effective final product.
WHAT TO EXPECT DURING THE PROTOTYPING PHASE
During the prototyping phase, your company will test and revise the design and specifications for your final product. This essential step begins with the creation of your initial design and then the creation of a prototype by the manufacturer or a manufacturing partner. The following must be determined when creating a prototype:
- Material selection: When choosing a prototype material, consider the physical requirements of your product and your goal for the prototype. Prototypes used for testing should closely resemble the dimensions, weight, flexibility, strength, tactile and other physical characteristics of the actual product. If functionality will be tested, whenever possible the material for the prototype should be the same as the material being considered for the finished product. If the final part must show the same behavior at a wide range of temperatures, or if resistance to chemical substances such as cleaning agents, biocompatibility or hypoallergenic characteristics are needed, LSR is an excellent choice. Depending on the prototyping technology, the materials available may be limited.
- Color selection: If aesthetics is a consideration, prototypes and display models can be used for product demonstrations. Display prototypes should showcase the aesthetic appeal of a product and color to elicit emotions from end users, and variations to test the color preferences of your customer base. When creating a prototype with LSR or silicone materials, the prototype manufacturer can mix custom colors to match your specifications.
- Multiple prototypes: After creating and testing the first prototype, additional prototypes can be produced to reflect any necessary adjustments or refinements. Often companies create multiple prototypes before finalizing their product design and specifications. Make sure to communicate design iterations early on to allow a steel-safe approach when building prototype inserts. New prototyping technologies make it feasible for companies to test various design iterations affordably and efficiently.
The prototyping phase comes to a close when the design is approved. The part design is finalized (“frozen”), and depending on the option chosen, production tooling or actual parts production can commence.
There are several options available for producing prototypes depending on the purpose of the prototype, the prototype material, and the physical properties required for the model. Prototypes can be created with tools or molds, or utilizing 3D printing technologies. These are the two primary options for prototyping.
RAPID MOLDS FOR LSR PROTOTYPES
Molds used to create prototype parts can be made in a variety of materials, including thermoplastic, aluminum, and steel. Lead times to produce prototype parts using molds are typically longer compared to 3D printed parts (a few weeks vs. a few days), however, the prototype parts offer physical and dimensional accuracy advantages and processing takeaway benefits.
- Thermoplastic mold: FDM or 3D printed technologies can be used to produce a form mold using a plastic material. The molds are manually injected with LSR and the material cures. The LSR prototype parts are then removed from the mold after curing.
- Aluminum mold: Sometimes referred to as “soft tools,” they are made of a special grade of aluminum. The tools are dimensionally accurate, can produce nearly all part details, and are run in molding machines to producing LSR prototype parts. Their production capacity is limited, usually around 1,000 parts. Lead times can vary however these quick turnaround tools typically are produced in 6 weeks or less.
- Steel mold: These tools made of steel are pre-production tools and are dimensionally accurate, produce all part details, intolerance, and do not require de-flashing or other secondary operation. Design modifications can be made to the tool to accommodate design changes. Upon completion of prototyping and finalization of design, the tool is ready for production eliminating the time needed to start the production tool building process and qualification. Although lead times can be up to 10 weeks once the design is finalized the tool can begin running production.
- Steel insert run in a mold base: Some manufacturers have low cavitation mold bases used for running tool inserts for a more economical solution.
Because these functional prototypes are very close approximations of actual production parts, they are effective for testing purposes. Manufacturers can use LSR prototypes produced through rapid tooling to test part functionality and gather critical product information that can be adjusted before production.
RAPID PROTOTYPE PARTS WITH NEW PROTOTYPING TECHNOLOGIES
New 3D printing technologies provide a viable option for rapid prototyping parts primarily for thermoplastic materials. 3D printing with LSR is still in its infancy stage, with limitations in material choices and resolution, but is expected to become available on a larger scale within the next five years.
Because 3D printing does not require a mold or tool, designers can refine part designs quickly and easily. 3D printers can also run unattended further streamlining the process. There are several options available using this type of technology, each with varying benefits and challenges.
- Fused deposition modeling (FDM): FDM 3D printing builds parts by extruding a heated thermoplastic through a nozzle and depositing it in thin stacked layers. When the layers cool, they form a solid part. FDM is typically the most affordable and widely available method of 3D printing and uses a variety of materials. The materials include PLA, ABS, PET, Nylon, TPU (Flexible) and Polycarbonate thermoplastics. However, depending on the product design, FDM prototypes may require supports. FDM 3D printing also has longer build times than other 3D printing methods.
- PolyJet: PolyJet 3D printers use a printer head to deposit special photopolymers (rigid and soft) in thin layers and then cure it with UV light. PolyJet 3D printing produces high-resolution prototypes with fine detail and a smooth finish. Because they use linear paths to print parts, PolyJet 3D printers can print multiple parts at once and have short build times. However, prototypes created with PolyJet 3D printing may not be as durable as prototypes created with FDM.
- Selective laser sintering (SLS): SLS 3D printing builds parts by sintering powered materials with a laser to form solid objects. SLS 3D printing uses various materials including Nylon, flexible TPU, and Polystyrene to produce products in many different colors. This method can create complex parts without requiring supports. However, the upfront costs and operating expenses of SLS 3D printers can be high.
- Stereolithography (SLA): SLA 3D printing technology uses lasers to selectively cure a cross-section of resin to build solid parts layer by layer. Special materials are used with characteristics similar to ABS, and flexible and rigid elastomers. SLA 3D printing produces prototypes with a smooth finish and high resolution. SLA technology can produce complex parts and components and are compatible with translucent resins. However, SLA 3D printers are often more expensive than other methods and have specific power requirements.
- Multi-jet modeling (MJM): A more recent development in 3D printing, MJM 3D printing works similarly to PolyJet 3D printing to produce high-resolution prototypes with fine details. Resins available are ABS and SEBS. This 3D printing method is suitable for tiny parts. MJM 3D printing also has the benefit of easy removal of the wax support structure after printing. One downfall of MJM 3D printing is longer build times due to thinner deposition layers.
- Liquid Additive Manufacturing (LAM): Uses layering technology similar to FDM to apply layers mixing the 2-part liquid silicone to build the part, and then cures using heat or UV light. This is the only technology on the market that uses true silicone with comparable mechanical properties to the LIM silicones used during injection molding production, and therefore creating a prototype part with mechanical properties representative of a production molded component.
Recent advancements in 3D printing technology have made 3D printers more affordable and accessible. However, 3D printing does not offer the breadth of materials and is not yet cost-effective for large batches of products due to its high unit cost. When large quantities of prototypes are necessary, such as for product testing, creating molds for prototypes is often more feasible. 3D printing also poses some challenges with precision when prototype design involves fine features or thin-walled parts.
CHOOSING A PROTOTYPE TECHNOLOGY FOR SILICONE PROTOTYPES
Depending on your desired prototyping method, various technologies are available for silicone products.
RAPID PROTOTYPING WITH 3D PRINTING
Companies can now create thermoplastic and LSR prototypes rapidly and affordably using 3D printing technology.
FDM 3D printing enables the production of thermoplastic polyurethane (TPU) parts and products in less than one week using a fused filament deposition (FFD) printer. TPU 3D-printed prototypes are available with different shore hardness’s. These prototypes have coarse details and a ribbed surface due to the manufacturing process. Because they do not require post-processing, it’s possible to create TPU prototypes with short lead times. FDM prototypes are effective for functionality and conceptual testing.
Recent advancements in 3D printing technology have enabled manufacturers to 3D print parts and prototypes using silicone rubber. Using UV-curing silicone or other two-component liquid silicones, companies can produce LSR 3D-printed prototypes in one week with up to 10 samples. Like prototypes created with FFD printers, 3D printing LSR parts results in a ribbed surface quality with coarse details that do not require post-processing.
FORM MOLDING FOR SILICONE PARTS
3D printing technology has also enabled faster prototyping for silicone parts using form molds. Manufacturers can use FDM printers or other 3D printing technologies to rapidly produce thermoplastic molds for prototyping. Silicone is then hand-injected into the mold and cured based on its material properties. After form molding, silicone parts require some post-processing depending on the desired surface finish. Using 3D-printed molds, companies can produce LSR prototypes in under 10 days to significantly reduce lead times.
Silicone prototypes produced with 3D-printed molds can have a ribbed surface or can receive post-treatment of grinding, ice blasting, or chemical polishing to create a smooth finish. All silicone-formed prototype parts require post-process de-flashing regardless of finish. With prototype over-molding, companies can use nearly all LSR types and produce complex and detailed geometries. For enhanced strength, manufacturers can add core pins and other support structures.
Milled alloy molds can also create hand-injected silicone formed prototypes. As with thermoplastic molds, form molding with milled alloy molds is possible with nearly all LSR types and can produce almost any variety of geometric detail. Milled alloy molds can create more surface types than 3D-printed molds, but still require post-processing to remove flash. Silicone prototypes produced with milled alloy molds can include support structures and cure at a high temperature for fast processing time. Manufacturers using milled alloy molds can make prototypes in fewer than 14 days.
RAPID MOLDS FOR LSR
Quick turnaround tooling or injection molding for LSR is another efficient prototyping technology that is well-suited for larger batch prototype production. LSR prototypes produced with tooling provide excellent detail and are close approximations of the final product. All surface types are possible with rapid tooling, and it’s possible to include core pins. Rapid tooling for LSR can produce accurate functional prototypes quickly using soft aluminum molds or steel tool inserts.
Rapid tooling with soft aluminum molds can produce LSR prototypes in under six weeks. Prototypes created with all LSR types offer close detail and surface quality that is near-production quality parts. All geometries are possible with soft aluminum molds, but post-processing de-flashing is required. Prototype injection molding with soft aluminum molds has somewhat limited production capacity (1000 parts), and retooling in steel is necessary for production parts.
Steel tool inserts can create LSR prototypes in about 10 weeks. As with soft aluminum molds, virtually all grades of LSRs can be molded with these steel tools, and all geometries are possible. Steel tool inserts offer a higher level of detail than soft aluminum molds, and do not require any post-processing. Another benefit of using steel tool inserts for injection molding prototyping is a seamless transition to part manufacturing using the same tools.
A consideration when injection molding prototypes is the unit cost will be higher for small batches. Because rapid tooling requires the creation of a metal mold, the initial expense is higher, however, companies must balance this initial higher unit cost with the value of speed to production and the low unit costs when in full production.
BENEFITS OF LSR PROTOTYPING WITH SIMTEC
SIMTEC Silicone Parts is a leading silicone rubber injection molding company that specializes in LSR (Liquid Silicone Rubber) parts. We are experienced leaders in 2-shot and multi-shot injection molding technologies that combine LSR with plastic or other substrates.
Although SIMTEC does not supply rapid prototypes, for programs requiring long-term, large-volume production we work with our customers early in the design process, assisting with aspects of industrialization including design optimization for productive and efficient mass production, as well as building steel tools/inserts to produce functional silicone prototypes in a wide range of LSRs with various shore A hardness values to meet our customers’ product requirements.
LSR’s versatility offers several advantages over other materials. Because LSR’s are hypoallergenic and biocompatible, they are well-suited for medical parts. LSR also offers excellent thermal stability to withstand extreme temperatures and high compression, making it an ideal material for use in the automotive industry. Harsh environmental factors or use of cleaning products common with many industrial and consumer products is also well tolerated due to LSR’s excellent chemical resistance.
Whatever your goals are for LSR prototyping, SIMTEC provides customized solutions to match your part specifications and production timeline, from prototyping through mass production.
CONTACT SIMTEC FOR PROTOTYPE MANUFACTURING
If your company needs high-volume production of silicone rubber parts, SIMTEC can assist with the LSR prototyping phase through to mass production. When you work with SIMTEC to for silicone product development, our engineers will get involved early in the process and work closely with your engineering team to optimize LSR part design and specifications. At the end of the prototyping process, SIMTEC engineers help ensure a successful transition to long-term, large-scale production.
With extensive experience providing LSR parts to Fortune 100 companies and other top businesses, SIMTEC has a track record of success and an enduring commitment to excellence. Contact us to get started with your high-volume production needs for LSR prototypes, parts, and products.