Machine drawing

Power capacitors are installed to compensate for the reactive power, particularly that which the machine draws from the grid. The capacitors must be suitable for a minimum voltage of + 13% (generally V, + 15%). 

Optimum conditions for conversion to form I (as monitored by ATR spectra) were established by preliminary drawing runs using an in-line tubular furnace. It was ascertained that machine draw ratios of between 5 1 and 6 1 at draw rates up to 3m/min were required to achieve substantial conversion. A linear relationship between tube density and furnace temperature was observed for a fixed machine draw ratio of 6 1. Over the temperature range 115°C to 170°C the density varied between 1.7886 to 1.7988 g cm"" which corresponded (assuming complete absence of form II) to a percentage form I content of 38.3% to 41.8%. 

Table 1 gives the percentage form I, form II and amorphous content of tube drawn during another set of runs at a furnace temperature of 165°C and machine draw ratios of 4 1, 5 1 and 6 1. The results were calculated from a combination of X-ray measurements which gave the form I to form II ratio and density measurements. 

TABLE 1. Crystal form content vs. machine draw ratio... 

The smaller crystalline content of the 6 1 machine draw ratio tube compared to the 4 1 tube is possibly a consequence of the faster kinetics allowing less time for crystal regrowth. 

An attempt was first made at poling after the neck. The 6 1 machine draw ratio tube (OD 1.4 mm, wall thickness 290 ym) was poled at a corona voltage of +30KV, 15 seconds after it had emerged from the furnace where necking had occurred, but only a low g coefficient of 4.9 x 10 2 Vin/N was obtained. 

Tube No OD (ym) Wall thickness (ym) Machine draw ratio True draw ratio Draw speed (m/min) Corona Voltage (kV)... 

X-ray results on the tubes showed that in both cases the crystal content was virtually all form I, indicating that possibly form II to form I conversion occurred on poling the lower draw ratio tube 1, where incomplete conversion to form I had been obtained on drawing alone. The densities of tubes 1 and 2 were 1.7887 and 1.7744 g cm 3 respectively, corresponding to form I contents of 38% and 35%. Slip had occurred between the caterpillar haul-off rubber tracks and the tubing, and consequently the true draw ratios measured by tube dimensions were less than the machine draw ratios obtained from the haul-off speeds. It is encouraging to note that the coefficients in... 

The third and most successful approach was accomplished on a wheel-type blow molding machine. Unlike the shuttle machine where only gravity acts on a downward extruded parison, a wheel machine draws or pulls the parison from the die. This allows extension in the extrusion direction and the opportunity to thin down the barrier layer and reorient the mica platelets. 

SO acts as a focus for stress concentration. During drying and in machine draws, local stresses are set up in the sheet. If the local friction between the filler particle and the fibre surface is large, then the fibre network locks until the drying stress exceeds the local failure stress. When local failure occurs the water meniscus between the fibres may be broken the fibre surfaces are then too far apart for hydrogen bonding to develop and reconsolidation of the bond is unlikely. 

Portable grinding machines, drawing knife, suitable equipment for the removal of surface unevenness (e. g. milling cutter), cleaning appliances buckets, clothes, sponges, water containers, brooms. 

Machine Drawings/Parts Lists Machine and Apparatus Technology... 

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