Press brake maintenance can be summarized in five points:
- Keep It Clean
- Keep It Tight
- Be Safe
- Use Common Sense
- Follow Scheduled Maintenance
Let’s look at how these principles should be followed at the different stages of purchasing, setting up and operating your press brake. (Please note that the timetable listed below is a general recommendation and is presented for educational purposes. For best results, always follow the maintenance schedule outlined in your specific press brake manual.)
Before You Buy a Press Brake
Maintaining your press brake should begin long before you actually purchase your machine. Your operators, shop staff and even managers have to have an attitude of maintenance about all of your equipment and your whole work area, or your new press brake will begin to incur costly problems right from the start.
Are your machinery operators following scheduled maintenance for the machines you already own? Do they keep the machines and the shop clean? Operators and shop workers tend to leave parts, tools and even junk lying around a shop near machines. Your people need to be in the habit of keeping all machines and work areas clean, or issues with safety and productivity will arise, not to mention damage to your machines because of dirt.
When You Buy a Press Brake
When you purchase any new equipment, especially something like a CNC press brake, do you have the personnel on staff who are trained (or are capable and willing to be trained) to run your new machines? Complex equipment like lasers and CNC machines require trained personnel to operate them correctly without taking shortcuts or doing any second-guessing that could damage parts, the machines themselves or especially people. Depending on what machines you are buying, you will want to budget enough to train your staff or possibly even hire new operators who will run and maintain them correctly.
Many machines will come with features that make processes easier or safer. An example would be adding a tooling system to a press brake that quickly and accurately seats tooling. Such a system will not only save time but will also likely prevent damage that could occur with improperly seated tooling. Be sure to look at what options are available with your new press brake that can make maintenance easier by eliminating potential problems.
It’s always wise to make a copy of your press brake manual. If it comes as a printed manual, see if the seller or manufacturer will also provide a digital copy that you can keep as a backup. If not, take the time to photocopy the manual or scan it as a PDF. If your manual comes as a digital file, it is recommended that you print it out and put the printed copy in the electrical panel where it’s accessible to operators and service technicians alike. If the digital copy comes on a thumb drive or CD-ROM, you should store that somewhere safe, away from the machine.
A manual is as essential to your press brake as tooling, but operators tend to misplace them, and replacements can be very costly to get. A good deal of billable time can also pass while an electrician or other technician is waiting around for your staff to locate the manual or obtain a replacement.
When You Install a Press Brake
If you wait until you power up your press brake for the first time to start practicing maintenance, it’s probably too late. Unfortunately, many press brake buyers start to experiment with their machines before they are fully installed by the seller or other trained professionals. More often than not, doing so creates all sorts of problems and even occasionally inflicts serious damage to the press brake.
After you’ve purchased your new brake, there are some tasks that need to be taken care of before the installation crew arrives:
- Make sure the press brake is exactly where you want it.
- Make sure that it is ready to be anchored to the floor.
- Make sure that it is ready to be leveled.
- Make sure that it has power run to it — but NOT connected!
- Make sure that it has oil in it.
- Make sure that you then leave it alone and wait for the installers.
Proper press brake installation and calibration is critical — if it isn’t done correctly, your press brake will never work exactly right.
At the Start of the Workday
Every morning when your operator is ready to begin work, he or she should clean the area around the press brake to remove hazards along with dirt that can get into the works. Your operator should wipe down the tooling and other surfaces of the brake with a dry cloth to remove any visible dirt, dust or foreign objects. These are enemies of your press brake and can be especially harmful to your tooling, so it is essential that your operator and staff keeps your press brake wiped down and clean.
Your operator should also wipe down the safety lasers with a clean, non-abrasive cloth that is specifically reserved for that purpose. Both a build-up of dirt as well as scratches on the lens can diffuse the laser light so that it isn’t focused correctly on the receiver.
When Preparing a Job
A press brake is only as good as its tooling, so your operator should always use the highest quality tooling with each job. If your press brake is using old, worn tooling, not only will it limit the accuracy of the part, but it will also affect the performance of your machine.
As your operator loads the tooling for a job, he or she needs to make sure it is seated correctly. The upper tool should always be seated under a small amount of tonnage to make sure it goes all the way up into the tooling holder. The operator also needs to periodically check and verify that the tooling is aligned correctly. When a press brake starts to have problems, a key troubleshooting step is to make sure that the tooling is correctly aligned.
Mill scale and other dust and debris will flake off of metal while it is being bent, and grease and oil can also collect dust and dirt. Some of this will build up in and around tooling, even working its way under dies. Your operator should wipe off the working surfaces of the tooling when it’s being changed, along with the top part of the upper punch where it seats and also under the bottom die. Grit and dust that gets between the tooling and the machine can change the accuracy of the job. A bend can be thrown off by as much as two degrees if the height of your press brake tooling is changed by as little as two thousandths of an inch due to buildup of dust and debris.
While the Press Brake is Operating
It is a good idea for a press brake operator to keep the tooling clean to sight on the exposed surfaces as it is being used. Your operator should also listen for unusual noises while the press brake is operating and check right away if something sounds or feels off. Just like with a car or truck, a rattle probably means something has worked loose.
Operators should always bend parts in the center of the press brake, even if you have a Y1/Y2 machine and it is a small part. Following this common practice will keep everything equalized and reduce the need to make adjustments later, as well as reducing the strain on the brake.
Press brakes are always moving and flexing, so an operator needs to keep an eye on anchor bolts while the machine is operating. If the press brake doesn’t stay level and anchored while in operation, bends can be thrown off and the movement can also damage the machine.
When a Job is Finished
Press brake tooling should not only be cleaned when it is changed, but it should be cleaned between each job, even if it is being left in the machine. This will help your press brake stay accurate. Any spills or debris should also be cleaned up around the brake between jobs.
At the End of the Workday
Pressure can bleed off when a hydraulic system holds the ram up, so a basic press brake practice is to park the ram in the bottom position when it is finished being used. Your operator should lower and rest the beam with the punch completely down in the die. To preserve your tooling, your operator can remove them and rest the weight of the ram on blocks of wood or other material instead. The ram should also be parked before any maintenance is performed on the hydraulic or mechanical systems.
The operator should once again wipe down the tooling, back gauges, guides and other surfaces with a dry cloth at the end of each workday.
Weekly Press Brake Maintenance
Make a list of any weekly recommended maintenance from your press brake manual and post it prominently in the shop near the machine. Require that all operators and shop workers follow it, and have managers regularly check with them to make sure they are doing so. It would probably be a good idea to have a regular time near the end of each workweek where everyone in your shop follows a routine to clean and check each of the machines.
As a part of the general maintenance of your press brake, your operators should inspect as they are cleaning to see if any parts are working loose. It is important that the power to the machine be turned off, locked out and disconnected to prevent any injury or damage during thorough cleaning, as well as during any maintenance.
Many parts of your machine need to be lubricated weekly, so be sure to follow the maintenance schedule listed in your manual to identify which ones they are. If the manual lists service schedules in terms of days instead of hours, be sure to adapt the schedule accordingly if your shop has fewer than eight hours in a workday of if you are running multiple shifts in a day.
Heavy parts like your ram guiding system should be greased, while more delicate mechanisms like back gauge spindles should be oiled, since oil doesn’t pick up mill scale like grease does. You should clean as you lubricate, wiping away the excess grease and oil from surfaces. Your press brake should also have rust protectant applied to those surfaces that can possibly rust.
Touch screen controls on press brakes are delicate but essential components that can easily get dirty just from the natural oil from an operator’s fingers, let alone from hands that have been handling tooling and parts. Many operational errors can be avoided by having your operators regularly clean the touch screen with a microfiber cloth.
Monthly Press Brake Maintenance
Some moving parts of the brake may need to be greased monthly, so your operator should check the schedule in the manual to identify which ones need it. Hydraulic oil levels should also be checked monthly, and the same type of oil that is in the tank should be used to top it off.
Special care should be taken to make sure that the hydraulic pump motor is kept clean of dust and dirt, and the outside of all parts of the hydraulic circuit should be cleaned. The hydraulic system should be checked for leaks, and when the machine is switched off and not under pressure all hydraulic connections should be checked. The hydraulic tank’s air filter needs to be checked and cleaned monthly.
Your operator should also remove and clean the filters on the vents and cooling fan in the press brake’s electrical cabinets. If the filters become blocked by dust, the vital electrical components of your machine can overheat. For cleanliness and safety, the electrical cabinet door should be kept closed when it doesn’t need to be accessed.
At least monthly your operator should check and tighten all bolts and connections. A press brake that isn’t kept completely tight will develop problems as it vibrates while it is in operation.
Bi-Monthly Press Brake Maintenance
All grease fittings (Zerks) that aren’t maintained more frequently should be checked and lubricated about every two months.
If you have a CNC press brake, it’s a good idea to make a full backup of your control programming every few months.
Annual Press Brake Maintenance
The hydraulic oil and oil filters should be changed after every 2000 hours of operation, or about once a year. Existing oil must be drained and disposed of properly, then the tank should be cleaned, and a new oil filter installed. If the new oil is different in type or brand than the previous oil, the entire hydraulic system should be cleaned out.
All electrical connections and switches should be checked annually. While some checks have to be performed under power, safety precautions should be observed. For the rest of the electrical maintenance, the main power should be switched off and locked out.
A specialized service technician should be brought in annually to perform preventative maintenance on your press brake. He can check for problems in the electrical or hydraulic circuits that your operators aren’t equipped to diagnose. Many press brake dealers and service centers offer annual maintenance contracts that can save the cost of this service.
When Problems Arise
Even though your operator and shop staff may be knowledgeable, it is a good idea to keep a trusted service technician or company on speed dial for those issues that aren’t easily resolved. It is better to pay for a possibly unnecessary service call than to have a machine ruined by a know-it-all who assures you he can “figure it out.”
If you have a CNC press brake and there appears to be a problem with the control, first have your operator do what he or she would with a computer that locks up — just reboot it! Just like a computer, sometimes turning a press brake off and back on will clear out the glitch. You should completely shut off the entire press brake’s power and give it a minute for the electricity to drain from all circuits, then restart the brake and see if that fixes it.
Another trouble-shooting technique for a CNC control that isn’t running right is to try the machine with an old program. If it works correctly with the old program, then there is likely a programming issue with the new program. It’s cheaper to recreate a program from scratch than to pay for a service call.
Clean, Tight and Safe
If your operator uses some common sense, follows scheduled maintenance, and has a philosophy of keeping a machine clean, tight and safe, your press brake should serve you well and have a long and healthy life.