Surface blemishes

Buffiag may be only to remove surface blemishes such as iasect bites or minor healed scratches, or the buffing may be to make a suede surface. Newbuck is a light suedeiag of the grain of catde hide leather. Sheepskin suede is usually buffed on the flesh side of the skin. SpHts may be buffed to make buck shoe leather or heavy garment leather, often called ranch hide. The variations depend on the desires of the customer. 

Jetting Jetting is a condition that results when the mold design has no immediate impediment to flow and the plastics is ejected into a relatively large open volume. This jetted material becomes a weak point on the product and a surface blemish that is difficult to conceal. 

In this case study, an automotive supplier was facing an issue of surface blemishes on sun visor arms. 

Portions of the sun visor arms used in automobiles can be manufactured from glass-filled thermoplastic polymers. Several visor arms contained visible blemishes on the surface. Typically, the steel insert of the visor arm is overmolded with the glass-filled thermoplastic polymer. Manufacturers sometimes utilize striations on the steel insert to provide a mechanical interlock with the over-molded thermoplastic polymer. However, in an improperly controlled environment, the mechanical process that produces the striations can also be the source of contamination and cause surface blemishes in the final product. 

To diagnose the surface blemish problem several analytical techniques were employed. First, the samples were photo-documented. Since an aesthetic problem is by definition a problem with the visual appearance of an item, it is important to ascertain if all the defects are different or of the same nature. With close inspection, the sun visor arms were found to contain two distinct types of defects. Figure 1(a) shows what was called the Type A defect and Figure 1(b) shows the so-called Type B defect. These images were acquired using a stereomicroscope coupled with a digital camera. 

The second test, developed by the Society of the Plastics Industry, involved preparing an amount of bacon that covered at least 50% of the dinner plate surface area [2], The plate with the bacon layer was heated in a microwave oven set at full power until the temperature at the center of the plate area reached 121°C ( 5°C). The time period required to reach this temperature within the bacon fat was 5 min on the microwave unit used for this test Immediately after the cooking cycle, the plate was cleaned on the lower rack of an automatic dishwasher. The dishwasher cycle was set at normal and included a heated dry cycle. The water temperature reached 66°C ( 5°C). Once the cycle was complete, the plate was inspected for surface blemishes such as cracks or blisters. This test is considered the most severe of the three due to the extreme localized heat generated, which causes the difference between the thermal coefficient of expansion for the two materials to shear the interface resulting in delamination. 

With thermal surface impedance testing, heat is injected into the test objects surface from a hot gas pulse. The resulting surface temperature transient is analyzed to determine the bond quality in nearly real time. The surface temperature transients are sensed using an innovative noncontacting, emissivity-independent infrared sensor.27 This method is not adversely affected by surface blemishes or roughness. 

Pearl Cold As surface pattern Platelets follow surface shape, possible surface blemishes Rigid Chalky-white to yellowish... 

This type of problem can occur, for example, in cordite manufacture, where the detectives might be sticks rejected for e.g. surface blemishes, and we are interested in whether e.g., one method of packing the press cylinder gives less rejects than another. 

The pattern can be shaped with traditional carving tools or cut to size with a nichrome hot wire cutter, available from model plane companies.Complex patterns are best cut out as simpler subunits. The pieces are then joined with spray adhesive or rubber cement. These glues will vaporize along with the foam.Surface blemishes in the finished pattern can be filled w/combustible wax filler if needed. 

Root knot and other pest nematodes cause poorly colored, deformed potatoes with rotted areas under the skin, surface blemishes, and surface cracks. Control pest nematodes by applying a chitin or parasitic nematodes to the soil. Prevent problems by planting nematode-resistant cultivars such as Heart , Jasper , Jeweir. Kandee, Nemagold , and Nugget . 

The orientation profoundly affects flow, hence processability, as well as the product performance. It plays an important role in extrasion or injection molding where the anisometric particles may become oriented in a complex manner. Layered structures, weld lines, splice lines, swirls and surface blemishes are well known. Mold geometry (e.g., inserts) and transient effects make predictions difficult. It has been theoretically and experimentally shown that, when designing a mold for composites with anisometric particles, the principles developed for single-phase melts do not apply [Crowson and Folkes, 1980 Crowson et al., 1980, 1981 Folkes, 1982 Vincent and Agassant, 1986, 1991]. 

The hydrated lime should be air classified to ensure that at least 98 % of the product is less than 200 pm to minimise the risks of surface blemishes caused by... 

Where a, is the uniaxial tensile yield stress and for polymer-based materials this is usually taken as the maximum load if a distinet yield point is not exhibited. However shear yielding in tensile tests with most polymers can be achieved by carefully polishing the specimen edges in order to remove surface blemishes and thus avoid premature failure. If yielding does not oecur and brittle failure is obtained, the stress at failure should be used in the criteria which gives a conservative size value. Alternatively 0.7 times the compressive yield stress may be used. The loading time to yield (or equivalent) should be within 20% of the loading duration in the fracture test. 

The issues to be addressed Amanda alleges her foot became stuck in a small pothole, that the maintenance of the track was poor with many changes in level and many surface blemishes. The suitability and condition of the playing field is alleged as unsafe. 

Major Influences are sheet thickness, plastic viscosity, and melt index (Chapter 1), regrind (Chapter 9), sheet orientation (Chapter 1), draw ratio, forming temperature and pressure, and surface blemishes, blisters, blushing, scratch marks, and so on. A guide to troubleshooting the thermoforming process is given in Table 5-5. 

Block Rake. A surface blemish, having the appearance of a chain, sometimes occurring on plate glass. 

The removal of surface blemishes from glass-ware by reprocessing. 

Orange Peel. A surface blemish, adequately described by its name,... 

Pluck, Plucking. (1) A surface blemish sometimes found on pottery where the... 

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