 |  | Working on Grinding Machines (Institut für Berufliche Entwicklung, 10 p.) | ||
 |  | 5. The Technological Processes of Grinding | ||
|  | 5.1. Setting up the Belt Grinding Machine | ||
| | 5.2. Grinding of Wide Surface | ||
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The grinding machine is clean and without current (the mains are switched-off). The safety devices are removed. The required sand belt is placed on the belt roller carefully, in order not to damage the edges. With the hand wheel the necessary belt tension is adjusted. The belt should be able to be pressed only slightly.
All safety devices are fixed according to the directions. The coverings of the belt rollers and the cover of the upper free belt run belong to it.
In a short test run the running of the sand belt is checked. A run off center belt is adjusted by means of the belt running correction.
Now the machine table can be adjusted in the right height. Thus the piece of work is placed on the sliding table and driven under the sand belt. The right table height is reached if between sand belt and the piece of work are 5 mm of space.
Via the selection switch the running direction of the sand belt is adjusted. By switching on the exhaust device the machine is ready to use.
The piece of work is placed on the machine table, adjusted and set to the stop bar. For different processes it is possible to make the coarse grinding across the grain. Thus the surface first is evened up. The following length grinding is mainly for smoothing. The co-ordinated movement of the left and the right hand is important with grinding.
The left hand takes the grip bar of the machine table and carries through the to and from movement. The right hand takes the grip of the pressure shoe.
By the movement of the grinding table and the pressure shoe every part of the surface can be treated. You should pay attention that the pressure shoe is not guided too far over the edges in order to avoid a toppling over.
Guide the pressure shoe under constant pressure over the surface. Thus the grinded material is cut evenly and an even surface is reached.
Figure 4 - Technology of
grinding - cross feed
1 movement of the left hand (machine table)
2 movement of the right hand
With the grinding of support plates for a further sticking with veneer you will grind with a coarse sand belt lengthwise and transverse.
With the grinding of solid wood and veneered surfaces you first grind with a medium sand belt and then with a fine one. These two grindings are carried out with the grain. With the grinding traces of former working stages are removed and a smooth surface is reached. Quality control is carried out visually and by rubbing gently with the hand over the surface of the piece of work.
You must pay attention that the table guiding hand should not get into the area of the sand belt.The pressure shoe should lift up itself when not in use.
The recesses on the table should be closed after being used.
- The abrasive dust should be exhausted separately from the shavings and stored separately.
- No metallic objects should be ground on the machine because of the sparking there can occur explosion fire danger.
Which safety devices are situated on the belt grinding
machine?
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How is the quality control of the ground pieces of work carried
out?
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