Press brake maintenance begins before an owner even begins to operate his machine.
One of our biggest concerns has been when a press brake owner starts to experiment with his machine before it’s fully installed. When we sell a brake we ask the new owner to do certain things before we arrive to install it: make sure it’s where they want it, make sure it has power to it but we will make the connection, make sure that oil is in it, and make sure that it is ready to be anchored and ready to be leveled.
Beyond that, however, we ask them to leave it alone. If an owner or operator decides they want to start running it before we get there, all sorts of problems and damage can occur, and we’ve seen that quite a bit.
Proper press brake installation and calibration is critical. If it isn’t installed or calibrated correctly it will never work right. You might make your first part right, but you will fight to get it right every time after.
A press brake is a machine that is always flexing and moving. Even though you anchor and level your brake when you install it, your anchor bolts will start to work loose over time. Loose anchors are one of the things that can really throw your bends off, so they are something that you need to keep an eye on when you are running a precision machine like a press brake. Make sure your machine stays level, stays anchored and isn’t moving while it is operating.
As a part of the general maintenance of your press brake, you should inspect your machine as you are cleaning it to see if other parts are working loose. Also listen for unusual noises as you operate your press brake — just like you would with your car, when you start to get a rattle, look to see what’s loose on your machine. Check and tighten all necessary bolts and connections at least monthly.
Even on a Y1/Y2 machine, we don’t recommend off-center bending. While it can be done, we suggest following the very common practice of bending in the center of your brake. Everything will be kept equalized and you won’t have to fight it and make adjustments while putting undue strain on the machine. If you are bending a small piece, bend in the center. No matter what it is, it is better to bend in the center.
A basic press brake practice when you are done running your machine is to park it in the bottom position. Rest the beam down in the die or on blocks every night. It is much easier on the cylinders and valves when the hydraulics aren’t having to hold the ram up. No matter how tight a hydraulic system is, even if the brake is brand new, pressure can bleed off holding so much weight.
One of the most important elements to focus on in press brake maintenance is cleanliness. Dust and dirt are the enemies of your whole machine, especially your tooling. It is essential to keep your press brake wiped down and clean. Your machine should also have rust protectant applied to possible rusting surfaces.
Your back gauge needs to be kept clean to work accurately. Lubricate your rails and ball screws according to your manufacturer’s recommended schedule, but be sure to wipe off all excess lubrication so it isn’t collecting debris and other contaminants.
Your press brake’s electrical cabinets will usually have cooling fans or vent filters which can become blocked by dust, so they should be removed and cleaned or blown out at least monthly and as needed. Always keep the door to the electrical cabinet closed except when you are accessing it, both for safety and for cleanliness. The hydraulic pump motor should also be kept clean of dust and dirt.
Your press brake’s safety lasers must be kept clean in order to operate correctly. Any dirt on the lens can diffuse the laser, causing the light beam to spread out instead of being focused straight across. Scratches on the lens can also diffuse the laser, so be sure to use a clean, non-abrasive cloth to wipe off the dirt. It wouldn’t be a bad idea to have a specific cloth set aside that you clean the laser with every morning at start up to prevent any build-up on the lenses.
Another practice of good press brake maintenance is to keep the area around your machine clean as well. People always seem to have junk lying around everywhere in their shops and they tend to put things in places where they can get in the way. Keeping your work area clean can help prevent issues with safety and productivity, along with keeping dirt and dust away from your press brake.
As you bend metal on a press brake, you cause mill scale to flake off of your material, particularly when you are working with black iron. Regardless of what material you are bending, dust and debris will come off of the metal and will work its way down under your dies. Even if you are bending aluminum, there are fine particles along the cut edge that will break off. Any material coatings, rust-proofing chemicals, and built-up resin will also flake off during bending.
All of these particles are continually building up in and around your tooling, getting compressed and stuck to it. If you aren’t changing your tooling often — or even if you are, but don’t clean it in between uses — you can significantly affect the accuracy of your press brake. For example, if enough dust collects to change your press brake tooling height by two thousandths of an inch, you might throw off the accuracy of your bends by as much as two degrees.
Wiping oil — which can collect dust — and mill scale off of your tooling as you are changing it can make a huge difference in the long run. Besides cleaning the working surfaces of the tooling, you should also clean underneath your bottom die and wipe off the top part of your upper punch (where it seats to the machine). It is also a good idea to keep your tooling clean to sight on the exposed surfaces as you are using it.
Another issue that can affect your press brake tooling is seating. As you load and unload your tooling, make sure it is seating correctly. The upper tool should be seated under a little bit of tonnage to make sure it’s up where it’s supposed to be. You also need to periodically check and verify that your tooling is aligned correctly. Whenever you start running into problems with your press brake, one of the first things to check is to make sure your tooling is aligned.
Keep in mind, if you are using old, beat up tooling, you can’t expect to get perfect accuracy out of it. Your tooling always affects the performance of your machine.
If you are using a CNC press brake control and run into problems that you can’t figure it out, try restarting your machine. Just like a computer that locks up and has to be shut down to clear out a problem, “rebooting” your press brake is sometimes necessary. Shut the machine’s power completely off (the whole press brake and not just the control), let it stay off for 30 seconds to drain power from all circuits, then restart your brake. It’s not the most common issue, but it is the easiest fix for a machine, so before you call a repair technician that’s one of the first things to check.
A basic trouble-shooting technique for a CNC Y1/Y2 press brake having problems running a new program is to try the machine with an old program. We’ve known operators who decide that there must be a problem with a brake when all of a sudden something isn’t working right with a new program, yet the day before it was running just fine with a different program. If this happens to you, before you call a service technician, go back to a program that you know works and see how it performs. If it is working fine, then in all likelihood you may have created an issue in your new program as you were making it. You need to go back and go through and double-check what you’ve done or delete it and start over. This is a very common issue, since we all make mistakes.
More and more press brakes are coming with touch screen controls now and the cleanliness of the screen can affect the control’s performance. We’ve found many operators who think they are having problems with their screen and recalibrate it when it’s simply dirty and cleaning it would have solved the problem. People have natural oil in their fingers and get dirty hands while loading a press brake and all of that can leave a film on their control. You can avoid problems by regularly cleaning your touch screen with a soft cloth like a microfiber cloth.
An essential part of press brake maintenance is the proper lubrication of your machine, and you should clean as you lubricate. As you grease something the excess grease will start to come out on the surface, and wiping it off right away will prevent it from picking up dust and potentially causing problems.
Your press brake’s manual should have a diagram that shows required lubrication for specified parts along with a chart showing the estimated schedule to follow. Keep in mind that most of these are determined by an eight hour work day, so you will need to adapt up or down according to your actual work. For example, if you are running three shifts, you will likely need to lubricate three times sooner than what is recommended.
Your manual will also include other charts and timetables for scheduled maintenance, changing hydraulic oil, replacing filters, etc. For the longevity of the machine, it’s always best to follow the manufacturer’s recommendations in the manual for scheduled maintenance.
It’s a good idea to make a copy of your press brake manual. If your manual arrives with the machine on a CD-ROM computer disc or a thumb drive, we recommend that you print it out and put the printed copy in the electrical panel where it’s accessible, while storing the digital copy somewhere safe, away from the machine. Manuals are incredibly important, yet people constantly lose them and replacements aren’t always easy to come by. Your manual needs to be accessible to electricians and other technicians who come in to service your press brake (along with your own operators). Digging around looking for manuals while a tech is waiting can consume a lot of billable time.
If you follow all of the steps above (along with a dose of common sense), your press brake can have a long, healthy life and give you years of service in your shop.
