Transfer press

Injection Molding Machines Glow Molding Con-presion Presses Transfer presses Thermotorming Machines Molds i Die Auxiliary Equipment Liquid Depensing Systems Irrpregnators Plotters... 

Figure 2. Transfer press molding for a high consistency silicone system...

Until the 1960s TSs (thermosets) were primarily molded using compression or transfer presses (Chapter 14). At that time screw injection machines with modifications were developed to process TSs. These modifications included low to zero compression for screw depths, deeper channel depths, short length to diameter screws (L/Ds), tool steel construction, barrel cooling with heat transfer fluids, and spiral down discharge ends in place of non-return valves.3... 

Flowability determinations on reactoplasts according to the method set out in ASTMD 31 23-72 (USA) involve the forming of a spiral of a specified cross-section. Use is made of a pressing machine for transfer pressing. The 20 0.1 g of the material is placed in a chamber 25.4 mm in diameter. Tests are carried out at 150 3 °C, at a pressure of 6.9 0.17 MPa, and a piston velocity of25-100 mm/s. The cross-section of the spiral formed is a half-circle with a radius of 1.6 0.5 mm. The maximum length of the spiral is 1270 mm. 

Spiral flow ASTM D3123-83 Measure length of flow along spiral die at end of test Set pressure and temperature from transfer press... 

Transfer Complex Transfer press Hardened tool Thermosetting 0.04-0.25 mm 1.5 mm 3°—5° taper. i°-5 = Yes High... 

Thermoforming Compression Molding Transfer Presses Pultrusion Rotational Molding... 

Transfer presses enjoy even greater sophistication based on the need to preprogram the transfer unit to recognize the die adjust pitch finger travel and lift automatically. 

The largest rate molding area an injection or transfer press can hold closed under full molding pressure. 

Injection Molding Machines Slow Molding Compraslon Presses Transfer Presses Thermoforming Machines Molds Dies Auxiliary Equipment Liquid Doponslng Systems Impregrtators Plotters... 

Plunger pbn-j3r (1611) n. The part of a transfer-press or old-style injection machine that applies pressure on the unmelted plastic material to push it into the chamber, which in turn displaces the plastic melt in front of it, forcing it through the nozzle and into the mold. 

For coating, sizing or pigmenting in film transfer presses the primary purpose of the cover is both to provide a soft nip and to transfer the applied Hquid film uniformly to the paper web. Abrasion resistance is important for keeping the nip geometry constant, as the film thickness of the applied coat/size is extremely thin and any nonconformity in the nip results in nonuniform film application. Good wettability and film splitting properties are also required. 

As mentioned in Sec. 9.4.3, liquid transfer molding (LTM) is being increasingly used for reinforced plastics, or composites. Conventional transfer presses may be used in such... 

Figure 1.79 (b) shows the mold for the transfer molding process from the bottom. A press with a separate injection unit is required for molds of this design. Most commonly, these are presses with a hydraulic cylinder that is centrally attached to the mold table. This actuates the transfer piston which is linked to the machine control (transfer press). 

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