Answer to Question 1
In some operations, chiefly where the melting of the resin is the limiting factor in decreasing the cycle, a second barrel or chamber is added to the injection molding machine. This second chamber is the collection point for the melted resin as it exits from the screw or ram melting unit. The second chamber has a ram injector that can push the melt of resin into the mold even while material is being introduced from the melting unit. The combination of a continuous melting operation and an on-demand injection operation can speed molding significantly in some cases.
Answer to Question 2
Crystallization normally gives materials a sharper melting point. That is favorable in injection molding because it makes the material easier to heat to a uniform viscosity. Furthermore, the crystallinity usually means that the material will cool and solidify more sharply, thus decreasing the time that the material must be cooled. After the part is removed, residual crystallization is common. This continuing crystallization can distort the part. Therefore, cooling fixtures are often needed to ensure that the part will crystallize and complete cooling without part distortion.
Historian James Merrell notes several errors in Benjamin West’s famous 1771 painting, William Penn’s
Aquamatic pad and heating unit provide dry heat treatment to a patient’s arm.
What are examples of ideal forms?
Explain the myogenic autoregulation of the glomerular filtration rate
For the circuit in Figure 1, assume ideal diodes. The peak inverse voltage is approximately