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How to Select A Used Hydraulic Press
Used hydraulic presses are often used in production and processing, such as cutting, punching, dropping, bending, riveting, and forming processes all require the use of presses. Used hydraulic presses are used to process various parts by exerting strong pressure on the metal billet to make the metal plastic deformation and fracture, something that is not easily formed under pressure. However, hydraulic press procurement is a discipline, even if the user will operate and use the hydraulic press on how to buy a more suitable hydraulic press is also a fog. At present, there are many hydraulic press manufacturers in the market, mixed with fish eyes. Many people may be greedy for a momentary interest in the cheap price and choose to buy, long-term view this does not save money. Seriously, good products are not very cheap, and in turn, cheap is not good quality assurance. Product price and quality, in general, is the existence of the best combination, is usually said to be cost-effective, “value for money”. For hydraulic presses such as machines expensive is not necessarily the best, but the best must not be too cheap, it is recommended that customers more consultation, more investigation, more attention to detail. Should be a comprehensive consideration of machine stability and after-sales service and other factors based on a variety of assessments before choosing to buy.
1. Hydraulic press type selection Hydraulic press types, stiffness, precision, and use vary, should be based on the nature of the production process, batch, mold situation, precision requirements, and other reasonable choices. Generally, the production batch is larger, and more small and medium-sized parts can be selected for easy operation and high production efficiency of the crank hydraulic press; if the production of laundry drums such as deep drawing parts are best to use the hydraulic press for stretching.
2. According to their actual needs, determine the purchase specifications, should follow the following principles.
- The user should find out what the enterprise processing workpiece is, is there special requirements for hydraulic presses? Also, leave a certain margin to consider the demand after expanding the scale of the enterprise.
- The nominal pressure of the hydraulic press must be greater than the stamping process force. However, for processes with long working strokes, it is not just a matter of meeting the size of the process force, but must also be considered to meet its working load curve.
- The number of strokes of the hydraulic press should be in line with the productivity requirements.
- The stroke of the hydraulic press ram should be such that the required dimensions can be obtained at the height of the part and that it can be removed smoothly from the die after the stamping process is completed. For drawn parts, the stroke should be at least twice the height of the part. The closing height of the hydraulic press, the size of the working table, the size of the slider, and the size of the die shank hole should all meet the requirements for the correct installation of the die. For crank presses, the closing height of the die should be between the maximum and minimum loading height of the press. The table size should generally be 50-70mm larger than the lower die base of the die (one side) to facilitate installation, and the pad aperture should be larger than the projection size of the part or scrap to facilitate leakage The die shank size should match the die shank hole size.
How to Operate A Used Hydraulic Press Correctly
Improper press operation or die set-up is the number one cause of damage and downtime on used presses. Proper training of press operators and die setters will ensure that they follow the correct procedures. This will quickly reduce downtime.
1. Lubricate the brake spindle at all points of the manipulator before each shift, fill the rod ball head, etc. with an appropriate amount of No. 20-30 mechanical oil with a grease gun before each daily shift, and press the clutch area with an oil gun once a day before each shift. Clean the machine before stopping each shift.
2. Check the fasteners and make up for missing external parts. Check the clutch and spring, belt. Check each lubrication device of the machine tool. Check electrical wiring for breakage and aging, and motor and solenoid for normalcy. Check the accuracy and wear of the crankshaft guide. Check the brake, clutch, slider, closing block, and closing ring. Check the electrical control part. Inspection and adjustment of the machine table coupling bolts.
3. According to the different machine types and processing requirements of the press formulate targeted and practicable safety operating procedures and conduct the necessary job training and safety education. The using unit and the operator must strictly comply with the provisions of the safety instructions and operating procedures provided by the design and manufacturing unit, and use and overhaul them correctly. The general safety requirements for the operation of presses are as follows.
4. Before moving the hydraulic presses, check whether the operating part of the press, clutch, and brake is in an effective state, whether the safety guards are intact and working, and whether there are any abnormalities in the various parts of the crank-slider mechanism. If abnormalities are found, the necessary measures should be taken immediately and the machine should not be operated with the disease. Before the formal operation, the machine must be tested by idling, to confirm that all parts are normal before working. Before starting the machine, all unnecessary objects on the workbench should be cleared to prevent the sudden start of the ram caused by driving vibrations falling and injuring people or hitting the switch. Tools must be used for operation, it is strictly forbidden to reach directly into the mold opening to take things by hand, and hand tools must not be placed on the mold.
5. When adjusting the position of the workpiece or uncovering the workpiece stuck in the die in the die opening area, the foot must be off the foot pedal. Multiple operators of the same press should have a unified command with clear signals, waiting for a clear answer from the other party and confirming that they have left the danger zone before moving. The power supply should be switched off when there is a sudden power failure or when the operation is finished, and the manipulator should be put back into clutch neutral and the brake in the braking position. For press overhaul, adjustment, and in the installation, adjustment, and dismantling of the mold, the machine should be disconnected from the energy (such as electricity, gas, liquid), the machine stops running, and the slider is placed under the cushion for reliable support. The start-up switch of the second-hand machine tool is marked with a warning sign.