Press Brake

The fundamentals of press brake maintenance

Six tips on correct and complete operation.

Nowadays hydraulic press brake machines bear wide ranges of capacity from portative types of fifty tons to 3000-ton or greater custom models, like CNC plate supportives, controllable tools, adaptive bendig, utilizer interfacing technology. Bearing higher capacity today`s press brakes require the same maintaining operations the as old ones.

The 4 major aspects of maintaining press brakes are hydraulic circuitry, mechanic and electric systems and tools. Everyday checking and maintenance of the mentioned aspects are quite easy. The offered 6 instructions will make a change in bend procedure, wearout of systemic elements and the service life of press brakes.

1. Look around: At the working shift examine the press brake like airplane captains inspect the airplane. Inspecting each area allows noticing and addressing little troubles not to make them more serious. The machine should be in perfect cleanness. It is important for the tables and matrix areas not to have scales. In case the press brake is outfit at the former shift or other tools must be placed, check the leveling of punches and dies, as well as the tooling state. To gain precise shapes, the punch and die must not have dints. (Fig.1) No cracked tool must be applied. Dints and fractures show the tooling overstressing, so it has to be repaired or changed.

Positioning of each back gauge finger needs checking and must correspond to the read values of axis.

Be sure in the correct operations of each device: palm button, top buttons, e-stop, foot-pedal controls, directive light. Checking each of tnese components is very simple and quick and ensure the secure funcioning of the equipment.

In case of guard system existence, be sure about its proper setting and functioning in accordance with each specification. If any deviance, report to your supervisors and correct it pripor to putting the machine into action. As soon as everyday review operations are carried out, take on certain maintaining missions.

2. Take precautionary measurments.

Rams of press brakes have to be supported prior to operating maintaining procedures on the machines and hydraulic systems. Put the rams upon two-sized wood blocks or bring them down.

Block the electric systems to be sure they will not be turned on.

3. Checking hydraulic circuitry.

Hydraulic oil is the life source of the bend system. It is crucial to keep the cleannes of oil and to fill the tank. Oil levels must be checked regularly. It can be done visually on everyday basis. Inadequate levels of oil brings about operational errors of the plunger and hydraulic pump faults and reduce the service life of pumps. In case the machine is tooled up with hydraulic tooling clamp mechanism for punches and die clamp, inspect its oil levels as well. This one possesses its detached indicators of oil levels. It can be checked visually. For oil levelling adjustment and overflow prevention the rams must be positioned upwards.

Dirty bits can penetrate the hydraulic circuitry as a result of inadequate compaction. The tank cap seal and air breather should be in fine state. Air breathers are attached to the tank cap allowing flow of air flow into the resorvoir as soon as the oil gets pumped into cylinders, thus, interfering vacuum formation.

Operational troubles, deviations of pumps or valves are possible ahen dirty particles fall into the oil. Actually, the vast majority of hydraulic circuitry troubles occur beacause of polluted oil. Pollution will lead to the valve jam at in or off positioned damaging pumping mechanism as it causes the pressure get lost gradually. 

After 2000-hour operation the oil viscidity and capacity should be cheched. It is recommended to gain oil smaples and get your oil suppliers to dissect it. Later replace or filter oil according to the supplier`s recommendation.

Follow these offered tips every 2000 hours of operation.

  1. Tank and each absorbing filter should be cleaned completely prior to filling. Two kind of filters have to be cleaned: the screen one upon the pump entry and the high pressure one at the exit.
  2. Each filter has to be cleaned or replaced. Note their cleanness. Any filter appeared it inpure surroundings is not applicable.
  3. Airflow filter over oil resorvoir cap must be checked. It gets pured through compressed air, though based on the workshop surroundings, it might require more thourough cleanup.
  4. Hydraulic circuitry oil tooled up with servovalves should be of five-micron clearness. Try to apply oils that are alike in their properties and are advised by your manufacturers. This is not the case for proportional-valved press brake machines.
  5. Pumps and pressure relieving valve need checking for the utmost pressure. The machine sizes and its versions determine how many valves have to be inspected. In no case must the utmost pressures surpass the specifications of your manufacturer.

Progressive press brake machines bear built-in devices, on-screen precaution devices indicating mainaining requrement. (Fig.2) These devices activate as soon as oil temperatures excessively great or little or an oil filter needs replacing.

In the hydraulic circuitry maintenance pumping and connective elements are other important aspects to be considered.

Hydraulic connecting components need checking every year, for they can get faulted due to frictions or long service. In the aftermath of every maintenance air should be released not to spoil pumping or other items. 

4. Overview Mechanical Equipment.

Mechanical elements of the press brake, such as cylindrical screws, chain handles, guides, should get inspected at least twice a year. Connections of cylinders and rams must be checked on regular basis. Inspect each bolt or screw for tensity. Each loosened bolt must be checked through unscrewing. In case of any stretch they have to be replaced.

The back gauge and stop needs calibrating and realigning. Innovative press brake machines need to be lubricated at the least amounts of points. Keep moveable elements like the back gauge, guide system, ball bolts pure and lubricated, for it is crucial for the proper operation and long service life of a press brake. (Fig. 3)

Elements that require lubricating every week are: 

  • Guide systems of rams
  • Guiding encoder, encoder guide systems
  • Racks and gear systems
  • Ball bolts
  • Guiding and railing components
  • Gear segments.

Lubricating type should correspond to the recommendations of your machine manufacturer. Avoid overgreasing not to cause damage and contamination of elements.

Ram guidance adjustments are also included in the maintaining operations. There must be a correct gap amongst ram shims. Excessive gap creats inaccuracies in ram cycling, too little one creates too much heating on the machine elements. Adjustment of clearance should correspond to the recommendations of the manufacturer. They depend upon the models of press brakes. Ram adjustments should be made by skilled tecnicians. Clearance sample in Fig.4 is true for a nylon-gib materials. Old models apply bronze-gibbed materials.

5. Inspect Electric Equipment.

Check each electric connection and electric switch upon the press brake basic pavement once a year. While maintaining electric systems, switch off the major power switches locking out the systems. Though, some checkings should be carried having the power systems on. Then consider warning measurements. Watch out when the machine components are being disassembled and reassembled. Pure surroundings is required to disassemble the machine.

Tips on maintaining electric parts.

Each connection of every single terminal strip, relay, box on engines must be checked.

Every print circuitry board must be reseated, checked not to cause injuries (any fractured solder point, burnt element so on).

The voltage flowing out of power supply and transformer have to be checked.

Each cable or switch must be inspected to avoid deviations and improper functioning.

Fans also need checking to realize suitable operations

Note the secure operation rules (e-stop, two-handed control and so on).

Keeping inner pavement temperature in the recommended specifications of manufacturers is crutial. Provide inner, and cool fans function to air-condition the systems. Keep termal exchangers cleaned. Note that the electric pavement doors are close. Having done this, you will prevent contamination of electric parts.

6. Tool Inspections. 

Different tools require different maintenance. For instance, a fabricator regularly sharpens, grinds punch tools. Yet tools of press brakes must be ground and rearranged only by tool manufacturers.

For the extension of tool service life, decide on the proper tool for your applications. The used materials also determine the lifespan of tools. They should be without scales to be exposed to formation easily, or else drags will be created on tools resulting in their quick wearout.

Tools should be kept cleaned and away off mill scales. Inspect tools visually each time proir to using them. Tools with cracks, damage should be sent to tool manufacturers to have them evaluated, reconditioned or replaced. Applying tools with dents and cracks will putthe equipment and operators in danger.

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