The product manufacturing time become more and more short now because products udpate on the market change quickly. And product devolopment time also shorter and shorter due to the competition in the market. So to avoid heavy investment, now more and more manufacturer choose On-demand Manufacturing and Low Volume Injection Molding prototyping service at the begining to sell the product to the market. in this blog, we will share everything about Low Volume Injection Molding to help you understand this process.
What is Low Volume Injection Molding (LVIM)?
Low Volume Injection Molding is a method employed in manufacturing to create a quantity of plastic components, between 100 and 10,000 units. The tooling is designed only for low volume life time with soft steel material. This technique is ideal, for prototyping small scale production runs. Crafting items when large scale production is unnecessary or too expensive.
Application of Low Volume Injection Molding
Prototyping: For creating prototypes in the early stages of product development to validate the design.
Short-run Production: Ideal for market testing of new products or when full-scale production is not yet justified.
Custom or On-demand Manufacturing: Useful for producing customized products or quickly responding to market demand changes.
Comparision between low and high volume injection molding
| Aspect | Low Volume Injection Molding | High volume Injection Molding |
|---|---|---|
| Advantages | ||
| Cost-Effectiveness | Lower mold costs for small batches 100 – 10000 units | Higher mold costs, better for large volumes > 10000 units |
| Rapid Production | Shorter production cycles | Longer setup for production |
| Flexibility | Easy to accommodate design changes | Less flexible with design changes |
| Disadvantages | ||
| Durability | Soft steel molds may be less durable. | Steel molds are more durable, suitable for long-term production |
| Design Limitations | May have limitations due to mold material properties | Can handle more complex designs due to stronger mold materials |
Toolings for low-volume Injection Molding
3D Printing Polymer Tooling
Stereolithography (SLA) 3D printing can be used to make a plastic cavity and core of the tooling with a high temperature resistance plastic material. this tooling can be used for that kind of low melting point plastic injection.
Aluminum Tooling
Aluminum tooling is another good choice for low volume injection molding because Aluminum is a easy machinable metal, this can save time for manufacturing the tooling. Aluminum tooling usually to produce plats parts less than 1000 pieces because aluminum is not so strong to resist the impact of too many times injection.
Soft Steel Tooling
Soft steel tooling dose not mean the steel used for tooling is soft. this only compare with the hard tooling used for mass production. Two primary types of soft steel tooling used for low-volume injection molding are P20 and NAK80. Soft steel is harder than aluminum which have a better lifespan which means it can used for producing more parts and up to 10000 pieces.
A Comparision table about three methods above as below, you will see which one is suitable for your project.
| Mold | 3D printed polymer | Machined aluminum | Machined soft steel |
| Mold cost | <$100 | $2,000 – $5,000 | $10,000 – $30,000 |
| Lead time to final parts | 1-3 days | 2-3 weeks | 3-5 weeks |
| Ideal production volume | <500 | 500 – 10,00 | 1,000-10000 |
| Applications | Rapid prototyping Custom injection molding Short-run injection molding | Short-run injection molding | Short-run injection molding |
Common Materials for injection molding prototypes
ABS (Acrylonitrile Butadiene Styrene)
ABS have a low melting point and it is easy to injection molding. this material is wide used in various inudstry for opaque products such as Keyboard keys, protective headgear, automotive parts, consumer goods, sports equipment, and industrial fittings.
Polycarbonate (PC)
Polycarbonate is a strong and transparent plastic material. It has high impact resistance and high temperature resistance, used in lots of applications where high strenth is required such as Machinery guards, clear and tinted windows, LED light diffusers, and clear molds for casting.
Acrylic (PolyMethyl Methacrylate) (PMMA)
Acrylic is a lightweight plastic often used as an alternative to glass. it is transparent and high-gloss. they are mostly used in those application where high clarity is priority. it widely used in products such as Windows, greenhouses, solar panels, bathroom enclosures, and architectural, lighting and outdoor components.
Nylon (Polyamide, PA)
Nylon is a versatile plastic with good abrasion resistance and high strenth. it is suitable for high friction and wear resistance applications. it usually be used for Mechanical parts, casings, threaded inserts, and high-friction applications.
Polyoxymethylene (POM)
POM is also known as acetal, It can be injected into parts that require low friction, high stiffness and excellent dimensional stability. Because they have a highly crystalline structure, POM plastics are naturally opaque and white. it is widely used for Bearings, gears, conveyor belts, fasteners, eyeglass frames.
Low Volume Injection Molding Manufacturing Process
Design and Modeling
3D modeling software is used to create a detailed design of the product.
Mold Design
The mold cavity is designed to precisely match the final product’s dimensions and details.
Mold Manufacturing
Molds are made using methods like CNC machining or 3D printing.
Injection Molding
Molten plastic material is injected into the mold cavity under high pressure and then cooled to solidify.
Demolding and Post-processing
Parts are removed from the mold and undergo post-processing like deflating and polishing.
Quality Control
We check the components to make sure they are the size and work well according to the design requirements.
Small scale Injection Molding is crucial, for creating products and meeting market needs. The use of advancements such, as printing has improved this method making it more effective and cost efficient.
Injection Molding Examples
Here are some cases of Injection Molding prototyping.
More Share Rapid prototyping examples – KUSLA (kuslaprototype.com)
DESIGN TIPS FOR LOW-VOLUME INJECTION MOLDING PARTS
Select The Right Material
The first step for low-volume injection molding is to choose the materials for your product. this because the material you use for injection molding will affect the materials of the tooling you can use. high melting point materials requires high strength and high temperature resistance tooling material such as Aluminum and Steel. so, you need to evaluate functions of your product, choose those materials easy to be injected.
Refine A Part’s Finish
A common mistake in plastic injection molding is demanding a smoother surface finish than necessary, potentially impacting product functionality. this is increasing the complexity of making the rapid tooling. if really necessary, consider hand polish to use on the injected parts.
Consider Multi-Cavity Molds
use Multi-Cavity Molds can reduce a lot your production time of small volumes. this is easy to understand that once trial out, you can get more parts.
Make Draft For Easy Part Ejection
Even rapid tooling sometimes does not require draft angle on product, but, if possible, apply draft angle in the design, this will reduce issues during injection molding.
Adjust Wall Thickness In Both Directions
Wall thickness is important in plastic parts production. walls should follow the starndards to avoid shrinkage and wrap during the injection molding process. they recommend thickness of plastic is from 1.5mm to 3mm.
Address Weak Corners With Radii
Aluminum mold machining use end mills, which may not work for sharp internal corners. so, make a Radii to improve the part strength and also easy for tooling making.
FAQ About Low Volume Injection Molding
What is the minimum quantity for Low Volume Injection Molding?
It is generally advised to produce a minimum of 100 units using Low Volume injection molding.
How much does low volume injection molding cost?
A small and simple single-cavity plastic Low Volume injection mold usually costs between $1,000 and $5,000. Very large or complex molds may cost as much as $30,000 or more. On average, a typical mold that produces a relatively simple part small enough to hold in your hand costs around $10,000.
Kusla is a rapid prototyping service company from China that offers customized services for both metal and plastic rapid prototyping. If you have any needs, you can contact Kusla
