Assessments - 2, GPA: 4 ( )

Fabricante : Black & Decker Arquivo Tamanho: 2.96 mb Arquivo Nome : Língua de Ensino:

Electric hammers and chisels are ideal for breaking cores. WARNING! When coring through floors, cores generally drop from the bit. To reduce the risk of injury, provide proper protection for people and property below the coring area. Diamond Coring Factors that influence diamond core performance: • Amount of coolant • Dymorig rigidity • Dymorig condition • RPM of drill motor • Feed pressure applied to bit by operator • Amount of steel • Size of embedded steel • Age of concrete • Aggregate (size, type, hardness, abrasiveness) • Type of sand–manufactured vs. river (natural) • Operator technique • Operator care • Bit runout Operator Technique Core with consistent, firm feed pressure. Do not subject the bits to sudden impacts. Uneven feed rate cracks diamonds. Low feed pressure polishes diamonds, slows penetration and contributes to bit glazing. High feed pressure can overload the drill motor or can cause diamonds to pull out prematurely, particularly when coring embedded steel. Make the bit work, but do not try to jam the bit through the material. If vibration occurs: 1. Stop drilling. 2. Turn motor off. 3. Check for loose bolts, nuts and gib screws. Tighten if required. 4. Check for bit runout. Replace if required. If vibration continues to occur, remove the core and loose material. If vibration continues to occur after attempting these measures, return the rig to the nearest MILWAUKEE service facility. page 11 Water Water provides two main benefits during coring: 1. Water acts as a coolant, eliminating the heat caused by the friction of the coring action. This preserves the integrity of the diamonds, the bond matrix, the segment solder, and core tube. Without a coolant, the heat buildup during coring can cause all of these components to fail. 2. Water flushes loose, abrasive particles created during coring. These particles consist of aggregate, sand, diamond particles and various metals from embedded steel and the core bit matrix. The hole must be free of debris to allow the core bit to work. If loose particles are not properly flushed from the hole, an unnecessary drag will occur along the side of the core barrel. This can contribute to bit glazing through lack of power as well as motor damage through amperage increases due to bit resistance. In addition, loose particles tend to wear the bit tube, which can eventually result in the loss of segments. Monitor water flow. Water volume should be adjusted until water return is a muddy, solid color. Clear water or clear streaks indicate too much water volume. Excess water is a leading cause of bit glazing and failure. Other factors contribute to glazing, but water adjustment is one of the most easily controlled by the operator. Excessive water prevents adequate segment/material contact. When the bit segments do not properly contact the work surface, the desired "controlled erosion" effect which maintains bit sharpness does not occur and the bit begins to glaze. This happens especially with smaller diam...

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