If you are having problems operating your Betenbender press brake, there are several things you can do to help you get back up and running without spending money on expensive repairs and upgrades. Use this guide for starters and then reach out to a professional when you have exhausted your options. 

1) What to do when your Betenbender Press Brake fails to start, or nothing happens. 

· Check the main disconnect switch to see if it is open. 

If it is closed, turn the disconnect switch ON.   

· Check to see if you have a blown transformer fuse. If a fuse is blown, replace it.

· Check to see if you have tripped central motor thermal overload relays. Reset the thermal overload relay. If the problem continues, check for issues that may be causing the overload relay to trip.

2) What to do if your Betenbender press brake has a primary motor overload.

· Check your thermal overload relays. The thermal overload relay prevents damage and loss of motor from overload and constraint conditions. Rectify the root cause of overload and reset. Read this guide on troubleshooting when the motor overload relay trips

3) What to do when your Betenbender press brake isn’t bending correctly.   

· If you see that your machine is producing jobs that are inaccurate or uneven you will want to check and make sure that the screws on the shaft are tight. If not, tighten the screws with appropriate tools. 

Check your machine for damage, wear or dings. Damaged tooling will cause your press brake to produce inaccurate bending. Replace any parts that are worn or not fastened correctly. 

4) If your RAM is not traveling down.  

· If your Press Brake RAM won’t come back down, it can be caused by blown transformer fuses. Your directional control valve may not be shifting. To troubleshoot, first, check the coil with a voltmeter. 

Replace the coil if it is not energizing. If the coil energizes but the valve does not shift, replace or service the valve.  

  • If the 125 PSI check valve is not allowing free flow to the cylinders, replace the PSI check valve if needed. 
  • The main relief valve may have failed or backed out too far.
  • Check if the dump valves are open. The dump valve is a safety valve that prevents down motion of the press when it is open. The dump valves are typically closed and energize only when the ram reaches the bottom of its stroke to stop its downward travel.
  • Precise limit switches control the RAM bottom reversal point. Check if you have crushed RAM limit switches. If so, replace the RAM limit switches. 

5) If the RAM does not return to the top.

  • Check to see if the machine is in the RUN position. 
  • Check if there is a broken solenoid coil. Replace if needed.
  • Check if the main relief valve is backed too far out or has failed.  

6) If your RAM fails to stop at the top or the bottom

  • The Top-of-stroke limit switch has failed and must be replaced.

If the ram moves up after being stopped by the top-of-the stroke limit switch, the directional control valve has failed to shift. 

  • Check the solenoid coil or for a stuck valve
  • The counterbalance valve may be sticking or stuck open.
  • The bottom limit failed.
  • The RAM control may be set too low.

7) Setting RAM Parallelism for your Betenbender Press Brake 

Different pressures across the press bed can twist the ram off parallel and damage the press or the tooling. As an owner of a press brake, you want to make sure the hydraulic press’ ram stays parallel. Here are steps you can take to set RAM parallelism of your Betenbender press brake. 

  • Cut 6″ square sheet metal coupons of thickness correct for die opening being used (1/8 of die width).
  • Lay one sheet metal coupon 6″ in from each end of lower die with the grain of material going the same direction on each metal coupon.
  • With the machine in JOG, bring the ram down to lower limits and hold the down button while cranking down the lower limit switches until sheet metal coupons are bent approximately 45ºF.
  • Let RAM back up and insert two new sheet metal coupons.
  • Cycle the ram down (in the rear) to stops and return.
  • Slide sheet metal coupons to center and compare. The goal is to have the sheet metal coupons with an equal bend. To reach this goal, adjust the micrometer on the right side of the machine. Adjust up to get more bend, and adjust down for less.
  • Make fine adjustments with a micrometer on the right side of the machine. You must make any future changes by using the micrometer on the right side. Using a touch up can of spray paint, repaint the left side adjusting the screw to identify any significant changes to the left side during operation.

8) Adjust RAM Timing 

After you set the Ram Parallelism and the ram is stopping at the same position on both ends, check to ensure the RAM is coming down at the same speed at both ends. Follow these three steps to adjust RAM Timing: 

  • Step 1) 
      1. Turn the RUN/JOG switch to the RUN position.
      2. While watching the indicator lights, located on the back of the control box, cycle the machine two to three times, noting which light comes on first. If both lights blink at the same time, the ram timing is correct. If not, proceed to step two.
  • Step 2) 
      1. If lights do not blink together: Loosen lock nuts on the adjustment knobs.
      2. Turn both adjustment knobs out to stops. Tighten lock nuts.
      3. Cycle the machine two or three times, noting which light comes on first
      4. Turn only the adjustment knob that corresponds with the light that comes on last, 1/4 turn. Tighten lock nut. Cycle the machine and re-check the lights.
      5. If indicator lights become closer to the same, continue to adjust that knob 1/4 turn at a time, to fine-tune, until the lights come on together, then lock the lock nuts. If not, proceed to step three.
  • Step 3) 
      1. If indicator lights become further apart, turn the knob back out and go to the other knob and turn it a 1/4 turn. Tighten the lock nuts. Cycle the machine and re-check the lights.
      2. If indicator lights become closer to the same, continue to adjust that knob 1/4 turn at a time, to fine-tune, until the lights come together, then lock the lock nuts.

Note: 95 Ton & larger machines have adjustment knobs located on the bottom side of the block. The adjustment knob on the 50 & 70 Ton machines is on the flow divider. 

CAUTION: — Never adjust both knobs to the in position at the same time. One knob is always out.

9) Zero Digital Readout on Adjusting Screw

  • Loosen backing set screw.
  • Rotate to 0000.
  • With the machine in JOG lower and bottom punch into widest deepest die being used and stop. (this may require lowering limit switches)
  • After verifying that readout still indicates 0000, tighten locking set screw.
  • The readout will now give operator reference from the bottom to repeat bends later.

10) Check for Oil Leaks

Check hoses for signs of leaks. Tighten as necessary.

Is it time to repair, replace or retrofit your Betenbender Press Brake?

Like a used car, the best thing about your old press brake is that you’ve already paid for it.    However, have you added up all those press brake maintenance and repair costs?  Labor costs, extensive setup time, and low productivity can all weigh heavily on the side of replacing your press brake.   Smart business owners have to consider all these factors before sending that press brake to the scrap heap.   Fortunately, there is another option that can extend the useful life of your press brake without the substantial replacement costs –  a Press Brake Retrofit.

Automec specializes in retrofitting used press brakes to extend its useful life and increase productivity.  Contact us at (781) 893-3403 for a free consultation on upgrading or retrofitting your press brake.

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