Last year was the safest year on record for commercial aviation, which we can all agree is good news. One of the many tools that helps keep us safe in the air is the pre-flight checklist. This simple device ensures the pilot doesn’t skip any essential checks before “pushing back” and taxiing to the runway.
We take a similar approach with our machinery. While none of it ever gets airborne, (a scary thought!) we still want to ensure it’s safe and reliable. To do that we carry out inspections. Checklists are a powerful way of making sure nothing gets overlooked. To illustrate this, here’s a look at how we approach shearing machine maintenance.
A Quick Overview of Shearing
Shearing is how we cut metal blanks for bending and welding. The machine has two blades, offset with a small gap between them for clearance, rather like scissors. The material is held flat and the upper blade brought down. This pushes the metal into the gap. It deforms at first, before fracturing downwards and along the blade direction.
Blade condition and clearance are critical to getting a good cut. Reliable operation depends on the pumps, motors, slides and bearings all being in good condition. Most important though is safety.
As with scissors, you don’t want fingers getting in the way during cutting. That’s why our shearing machines come with a guard. It’s also why safety comes top of our checklist.
Checking for Safe Operation
The guard must be in place every time the shears are used. It’s rule number one. After that we carry out an inspection to make sure everything is in order. We pay particular attention to hydraulic and pneumatic cylinders and hoses, and we make sure brake linings have plenty of material left on them.
Ensuring Quality Output
Before starting to cut we check the machine is going to produce an accurate blank with a clean edge. That means looking at:
- Blade condition – check for dings, dents or curvature
- Clearance – must be appropriate for the type and thickness of metal being sheared
- Backgauge condition and adjustment
- Hold down operation – to be sure the sheet won’t move during shearing
Shearing Machine Maintenance Checks
Good preventive maintenance is a combination of inspection, cleaning, adjustment and replacement. Some of this is covered under the heading of safety checks, but there are other things we look at too. This helps prevent breakdowns and ensures our machines have a long and productive life.
On our shearing machines we pay particular attention to gib clearances and fluid systems. The gib is the mechanism that guides the ram and blade. Too much clearance and it could twist and bind up. Too little and it might jam and certainly won’t cut well.
The fluid systems include hydraulic cylinders, along with pneumatics and lubricating oil. The oil is changed as the machine manufacturer recommends and if we spot any leaks they are put right immediately.
The Benefits of Checklists
As you can see, we scrutinize our equipment pretty closely. That’s because good maintenance pays for itself many times over in terms of safety, reliability and lifetime. Just like the airline pilots though, when we follow the same routine every day there’s always a risk of getting forgetful, and that’s where checklists come in.
A checklist guides the machine operator or maintenance technician through what they need to do. A second benefit is that it can provide a history of machine condition, particularly if there are fields for notes and observations.
Reviewing completed checklists lets us spot if something is changing. Perhaps a new hose needs replacing after just a few months, or maybe we’re adjust gib clearance more often. These are just two examples of how checklists help decrease downtime. You can probably tell, we’re big fans.