Client's Demand
A medical device company just finished developing a new medical device and was planning to make a small batch of new products to test the market. It is an automatic nucleic acid molecular hybridization instrument. The first batch was 5 sets. One is for trade fair and marketing material preparation, and the rest four is open for selling to its customers.
Machining Solution
The medical device is a typical large-sized product. For a short-run production of 5 sets of prototype plastic parts, vacuum casting is usually the most optimal and economical machining method. There were two kinds of plastic materials to make all the prototype plastic parts in this case: ABS-like material for the non-transparent parts, and PC-like material for the transparent part. After manufacturing, the non-transparent prototype plastic parts were painted in matte white, and the transparent ones were painted in transparent blue. The company logo was silk-screened on the enclosure.
What is vacuum casting?
Vacuum casting is a manufacturing method that produces PU (polyurethane) parts the same as the master via silicone molds under a vacuum environment. Because vacuum casting is cost-effective, easy to operate, reproducible, and highly efficient, it is widely applied for rapid prototyping and short-run production.
Our tips to ensure the high-quality prototype plastic parts via vacuum casting:
1. When the master surface is rough or we make a complex silicone mold, we will sand the master surface smoothly and clean it carefully to get a qualified silicone mold.
2. When making big-sized prototype plastic parts like this medical device, we will make metal supports inside the silicone mold to guarantee its strengths.
3. Also, we will use silicone mold with a hardness of shore A 40 - 50 to avoid deformation when making prototype plastic parts that are longer than 50 cm.
What is the vacuum casting material options for prototype plastic parts?
The materials for vacuum casting are different PU series:
· Common PU: more brittle and tough;
· Transparent PU: transparent plastic-like, more expensive;
· Rubber-like PU: 8400 soft rubber.
The properties of the parts can be ABS-like, PMMA-like, PC-like, PP-like, PE-like, PA-like, POM-like, PVC-like, soft-rubber-like, etc.
The processing steps include:
1. Making the master
Based on the 3D drawings supplied by the customer, the master is manufactured through CNC machining or SLA 3D printing.
2. Making the silicone mold
After making the prototype, we make the mold frame, fix the master inside, and pour silicone. After 8 hours of drying, cut the mold and take out the master, then the silicone mold is ready.
3. Casting the parts
Cast liquid plastic material into the silicone mold, after 30-60 minutes of curing in the thermostat of 60°-70°, we take out the part. Sometimes, second curing will be needed in the thermostat of 70°-80° for 2-3 hours. Generally, a silicone mold can last 15-20 shots.
After all the prototype plastic parts are ready, we assemble each set. We need to use metal mounts and screws, and also several nonstandard components which were CNC machined. The client would put all the electronic parts on their own. Occasionally, our customers send the electronic parts to us for assembly. Then they don't need to do extra work but receive complete products and mounted prototype plastic parts.
Final Work Showcase
FAQs of Prototype Plastic Parts
1. Can I choose to make prototype plastic parts through CNC machining and 3D printing?
CNC machining and 3D printing are also ways of making prototype plastic parts. X Rapid Technologies will provide the optimal solution within your budget based on the material, amount, part structures, etc.
2. Why the prototype plastic parts can serve as end-use products?
The prototype plastic parts made by vacuum casting have similar properties to parts produced by mass production. With adequate surface treatment, vacuum casting products can be end-use ones to be sold in the market, especially for medical devices,
3. What file formats does X Rapid Technologies accept for making prototype plastic parts?
3D files in CAD, STP, STEP, IGS, or X_T format are all OK for a quotation. STEP files are better for manufacturing.
4. Can X Rapid Technologies satisfy my special manufacturing requirements?
We are experts in custom manufacturing. Every project is different. We always deal with special manufacturing requirements. It is our routine to satisfy the special manufacturing requirements of our customers.
