Vacuum Casting: The Best Choice for Small Batch Plastic Parts

During the product development process, there is often an awkward situation: the cost of 3D printing a single piece is too high, while making a formal mold is too expensive and time-consuming, but the actual required quantity is only dozens to hundreds. Vacuum casting (also known as silicone casting) is the golden solution to this problem. Dongguan Yiruida Technology Co., Ltd. provides professional vacuum casting services with extremely low mold costs and fast delivery cycles, helping customers produce 10-100 small batch plastic parts, making product trials, market validation, exhibition samples, and small batch supply easy and controllable.

What is Vacuum Silicone Casting?

Vacuum silicone casting is a small batch production method based on silicone molds. The core principle is: first, a high-precision "master pattern" (Master Pattern) is made through 3D printing or CNC processing. Then, the master pattern is wrapped with liquid silicone and cured into shape. After cutting the silicone, the master pattern is removed, obtaining a silicone mold with a cavity. Under vacuum conditions, two-component polyurethane (PU) resin is poured into the silicone mold, and after curing, the mold is opened to obtain a replica identical in shape to the master pattern.

Key Data:

• One silicone mold can replicate 15-25 pieces (depending on product complexity and material)
• Delivery time: 1-3 days to make the master pattern + 2-3 days to make the mold and cast = total of 5-7 days to complete the first delivery
• Cost: only 1/10 to 1/5 of a formal injection mold
• Applicable quantity: 10-200 pieces most cost-effective (more than 200 pieces require 2-3 parallel molds)

Core Advantages of Vacuum Casting

Conclusion: When you need 10-200 plastic parts and require close to mass production quality with quick delivery, vacuum casting is the most cost-effective choice.

Our Vacuum Casting Capabilities

Master Pattern Production (Master Pattern)

The precision of the master pattern directly determines the precision of the replicated parts. We offer two methods:

• SLA 3D printed master pattern: suitable for fine appearance parts, smooth surface, fast and low cost.
• CNC machined master pattern: suitable for larger size (>300mm) or master patterns requiring higher strength and heat resistance.

After the master pattern is completed, it will undergo surface grinding, painting, and other treatments to ensure the surface quality of the cast product is excellent.

Silicone Mold Production

• High-temperature resistant, low shrinkage, high tear strength addition-type silicone is used.
• The parting line of the mold is designed according to the product structure, and multi-cavity molds can cast 2-4 pieces at once.
• Mold life: 15-25 casts (up to 30 times for simple products).

Castable Materials (PU Resin)

We can provide various colored PU resins, which can almost simulate the mechanical and appearance properties of all common plastics:

Surface Treatment Capabilities

Replicated parts can undergo various post-treatments like injection molded parts:

• Spray Painting: Matt, glossy, rubber paint, metal paint, UV varnish
• Screen Printing/Transfer Printing: Logo, patterns, scales
• Electroplating: Chrome plating imitation, nickel plating (requires special conductive primer)
• Water Transfer Printing: Wood grain, carbon fiber, camouflage, etc.
• Polishing: High gloss transparent parts polishing

Standard Process Flow for Vacuum Casting

Step 1 Obtain the Master Pattern

Based on the customer's 3D drawing, the master pattern is made using SLA or CNC to ensure precision and surface quality.

Step 2 Make the Silicone Mold

• Hang the master pattern in the center of the casting box;
• Pour the mixed and degassed liquid silicone;
• Place it in a vacuum chamber to remove bubbles;
• Cure in an oven at 60-80°C for 2-4 hours;
• Cool down, cut the parting line, remove the master pattern, and trim the mold.

Step 3 Vacuum Casting

• Mix the two-component PU resin in proportion and pour into the casting cup;
• Place in a vacuum chamber to degas;
• Slowly pour the resin into the silicone mold;
• Vacuum again to ensure the resin fills the cavity;
• Cure in the oven (temperature depends on the material, usually 60-80°C, 30-60 minutes).

Step 4 Mold Opening and Post-Treatment

• Open the silicone mold and take out the replica;
• Trim the gate and flash of the parting line;
• Perform grinding, painting, screen printing, etc.;
• Assemble multi-part products if needed.

Step 5 Quality Control

• Dimensional inspection (first piece and spot check)
• Visual inspection (color, gloss, bubbles, lack of material)
• Function test (assembly, load-bearing, temperature resistance)

Step 6 Packaging and Shipment

• Clean, static-free packaging, mark the quantity, and attach an inspection report.

Typical Application Scenarios

1. Medical Device Prototyping

A respirator face mask company needed to verify assembly and material feel before opening the formal mold. They used vacuum casting to produce 30 sample sets, with a cost only 1/8 of the formal mold, and successfully passed the clinical assembly test.

2. Pre-production of Consumer Electronics

A smart hardware startup developed a new smart speaker and needed 20 housings for crowdfunding samples and KOL reviews. The appearance parts obtained through casting were indistinguishable from mass production, and the delivery time was only 6 days.

3. Small Batch Supply of Automotive Parts

A modified car brand needed 50 custom car light brackets, requiring ABS material and heat resistance up to 80°C. Using vacuum casting, the cost was reduced by 60% compared to CNC machining, and each part had good dimensional consistency.

4. Robot Housing Verification

A robotics company needed 10 housings for exhibition displays before the new product launch. Vacuum casting provided quickly assembleable housings with complete spray-painted surfaces, successfully supporting the product presentation.

Why Choose Yiruida Technology's Vacuum Casting Service?

• Extensive process experience: we complete hundreds of casting projects annually, and we know how to control shrinkage rates of different materials and avoid bubbles and lack of material.
• High-precision master pattern: we have our own SLA and CNC equipment, no need for external cooperation, ensuring the quality of the master pattern is controlled.
• Comprehensive materials: we keep more than ten types of PU resins, from transparent to soft rubber, flame retardant to heat-resistant, all available for same-day调配.
• Comprehensive surface treatment: internal completion of spraying, screen printing, electroplating, etc., faster delivery, unified quality.
• Transparent small batch pricing: no hidden fees, the quote is the final price, we support customers bringing their own master patterns (subject to assessment).
• ISO9001 management: all production processes are documented and traceable, meeting audit requirements for medical and automotive clients.

Frequently Asked Questions (FAQ)

Q1: Can vacuum casting achieve the same material as injection molding?
A1: The casting uses two-component PU resin, whose mechanical properties and appearance can be very close to ABS, PC, PP, etc., but cannot be 100% identical. For non-extreme applications (such as appearance parts, general structural parts), customers usually cannot distinguish the difference. If strict equivalence is required, it is recommended to directly open the injection mold.

Q2: How many pieces can one silicone mold produce?
A2: Usually 15-25 pieces. If the product is simple, without sharp edges, and high-quality silicone is used, it can reach up to 30 pieces. If more quantity is needed, we can make 2-3 parallel molds and cast simultaneously.

Q3: What is the maximum size that can be cast?
A3: The maximum size of a single piece is approximately 600×600×400mm. Larger sizes can be split and cast separately, then glued together.

Q4: Can different color products be cast?
A4: Yes. PU resin can be dyed, and we provide Pantone color matching service. Each casting batch can customize one color, but only one color can be produced per mold batch.

Q5: Can the cast parts be screen printed or painted?
A5: Absolutely. The surface of the cast parts is similar to injection-molded parts and can adhere well to paint and ink. We can provide a one-stop service of grinding - priming - painting - screen printing.

Q6: Is vacuum casting the same as rapid tooling (RTV mold)?
A6: Yes, vacuum casting uses RTV silicone molds, which belong to rapid tooling. However, unlike simple injection molds, it does not require an injection machine; instead, it is formed by vacuum casting, suitable for small batches.

Evaluate Your Casting Project Immediately

Do you have a demand for 10-200 small batch plastic parts? Send us your drawings, and we will evaluate the feasibility of casting and provide a highly competitive quotation.

Yiruida Technology - Use small batch casting to pave the way for your product mass production.