Low Pressure Injection Molding

I. Why Low Pressure Molding (LPM)?

(slide 1)

1. Less Start-up Capital
   1. Semi-Auto machine $30-40K
   2. Auto machine $40-60K

2. Tooling costs substantially lower
   1. normally less than $10K usually less than $5K for single cavity semi-auto molds
   2. Tooling can be Aluminum

3. High Volume is feasible.

4. Can hold tolerances
   1. normally +/- 0.005' (0.1 mm) per inch (25.4 mm), some current projects being held to +/-0.001' (.02 mm)

II. What geometric and mass capabilities are viable with LPM?

(slide 2) Mach Nozzle

1. Parts less than a gram.
   1. 0.300' (7.6 mm) length
   2. 0.075' (1.9 mm) OD
   3. 0.011' (0.3 mm) venturi
   4. 200 point CAD Curve
   5. Approx. yearly usage 15000 pcs, 3 details
   6. 6% Co sub-micron

(slide 3) TJK Nozzle

2. Parts less than 50 grams.
   1. 20° angle, 0.058’ (1.5 mm) small orifice from 0.150’ (3.8 mm) dome configuration.
   2. weight 35 grams, Rockwell A 95+
   3. epoxied into a 17-4PH stainless steel casting and mechanically fixed with 2 ea. 6-32 1/8 set screws
   4. Approx. yearly usage 10000 pcs.
   5. 4.5% Co ultra grain

3. Parts less than 100 grams.
   1. one through hole
   2. one feed chamber
   3. 2 O-rings and 1 flat
   4. weight 70 grams
   5. 4.5% Co sub-micron

4. Parts from 100 to 500g.
   1. Gas Seat Check
   2. 3 series, 28 details per series
   3. details are to venturi size
   4. Constant 6° angle on ID for all details

5. 6% Co sub-micron

5. Parts more than 500g.
   1. 90° exit orifice
   2. 5° angle in shank
   3. 17-4 PH stainless steel shovel epoxied on
   4. weight 735 grams
   5. 12% Co 3-5 µm grain
6. Parts more than a kilo
   1. currently molding a 7.8 Kg disk, 11' (279 mm) diameter

III. Are ceramics viable with LPM?

1. Ceramic materials that have been low pressure molded by Retco
   1. Alumina
   2. Zirconia
   3. Ferrite
   4. Porcelain
   5. Yttrium Stabilized Cubic Zirconia

2. High volume is feasible
   1. 25K per week

IV. Does LPM have a place in today’s market?

1. Yes, today’s technologies are creating new and unusual wear and corrosion problems that only a cemented carbide can solve.

2. Serious "wear" problems can cause costly shut-downs and customer dis-satisfaction. LPM Carbide can be an effective means to solve this.

3. The lower cost of LPM allows the user to seek a better solution for his wear problems. In a lot of situations the user knows that WC is right for the application but it can’t be pressed and would be cost prohibitive to Preform.

4. The current development of the Ultra and Nano-grained Tungsten Carbides will send more users to carbide wear parts due to the cost effectiveness in terms of longer usage and less shut-downs.