Sharp SH-920 Instruction Manual page 45

(E) THE HYDRAULIC SYSTEM
A special hydraulic system for driving the longitudinal traverse of the table is
adapted. The table speed is variable and can be adjusted from 5 m/min to
25m/mn.
The hydraulic oil
1.
For trouble free operation, the specified oil Mobil Vacouline 1409 or its equivalent
one is recommended.
Change of new oil
2.
The oil is apt to oxidation contamination and ageing, it is recommended to have
the replacement of new oil after its first three months operation and every one
year operation of the machine.
The mix of new oil with highly aged oil is senseless. The addition of new oil can't
improve the quality of the old oil, but cause the added new oil become useless
rapidly.
How to test the hydraulic oil
3.
A simple way to test the degree of oxidation contamination and ageing of the oil
is:
Take a drop of hydraulic oil to the filter paper, if it appears light and yellow it
means the oil is clean and good. On the other hand, if it appears a dark
spot, it means the oil has been considerable aged, and has lost its quality.
Table shock
4.
4.1 If the hydraulic system particularly in pipe line having contained some air in
it, it will cause the table shock.
4.1.1 If pipe connections do not be fastened well, air will be sucked in.
4.1.2 During the operation of connecting the hydraulic tank to the machine,
air will have chance to enter into the system.
4.1.3 In case the air have already been existed in the system the remedy
process is to run the table with low speed at full stroke, after a long
period of operation the air will be squeezed out.
4.2 A too high pressure will cause the table to shock also.
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