You’ve been meticulous in choosing hardness testers, ensuring their efficiency and precision. The right equipment can deliver reliable results for years. But the integrity of those results may depend on the maintenance of your hardness testing equipment. Hardness testers require regular upkeep to stay accurate and safe, allowing the tester to meet industry standards.
How often should you run maintenance on your hardness testers? What specific tasks will you need to perform?
Here’s a practical guide to extend the lifespan of your testers, reduce downtime, and avoid costly recalibrations.
Determine the Schedule for Routine Maintenance
The routine maintenance of a hardness tester depends on a number of factors, not the least of which is the supplier or manufacturer’s recommendation. Because each equipment will come with distinct components and designs, the wear and tear patterns will differ.
The following factors can generally influence how often you need to check the hardness testing device.
Materials Tested
Harder materials (e.g., steel) will be tougher on the hardness tester than softer materials (e.g., plastic). As such, the maintenance schedule of a Brinell hardness tester will be more frequent than a Shore hardness tester.
The Brinell method focuses mainly on metals and alloys (e.g., lead, copper, aluminum, etc.), whereas the Shore method is primarily used on plastics and rubbers (e.g., automotive tire tread, pneumatic o-ring, ebonite rubber, etc.).
Frequency of Use
When you run more tests on equipment, it’s likely to wear out faster. Wear and tear can reduce the measurement accuracy of the tester as the moving parts undergo increased friction and stress. Frequent testing can also expose the equipment's surface to debris and dust, affecting the components.
Environmental Conditions
Some hardness testers are not limited to production floors; many can be used in the field or moved across various workstations. The environment in which the equipment is used will impact how often it requires maintenance.
Consider the equipment’s exposure to temperature and humidity, which can cause some components to expand. As you know, hardness testers require a temperature range to ensure performance. The American Society for Testing and Materials (ASTM), for instance, recommends testing at ambient temperatures from 50-95°F (10-35°C) for Rockwell hardness testing.
Abrasive particles and dust can also settle on the surface, which can wear down some components.
Your Hardness Tester Maintenance Checklist
Whether you perform the routine maintenance monthly or annually will depend largely on usage and the manufacturer or supplier’s recommendations. Generally, however, the following tasks are done on hardness testers to ensure the reliability and safety of the equipment.
Check for Wear and Tear
An initial inspection of the hardness tester allows you to detect problems before they create costly problems, from downtime to repairs or replacement. You’ll want to check the components for cracks, excessive wear, or chips. Look for misalignment and loose parts as well.
If it’s a Brinell tester, check the indenter for flattening or chipping of the tip and the loading mechanism for signs of binding and excessive noise.
Clean the Tester
A clean hardness tester lasts longer, ensuring its long-term service life. Although you might not use the tester every day, a daily cleaning schedule is good practice.
Regular cleaning prevents dirt and debris buildup on the surface. It also ensures accurate hardness readings.
Check the manufacturer’s manual for cleaning recommendations, from the cleaning solution to the procedure. In general, use a mild cleaning solution because harsh chemicals or agents may damage sensitive components. Microfibers or any soft, lint-free cloth are ideal for wiping down the equipment.
Make sure to unplug the hardness tester before cleaning it.
Lubricate the Components
Lubrication increases the lifespan of any hardness tester because it reduces friction. When the components continually move smoothly, the equipment also performs efficiently and accurately.
The lubrication points tend to be at the shaft, bearings, and gear. The manufacturer’s manual will specify the lubricant so that you use the appropriate one for your tester's operating conditions. The manual will also provide a schedule based on usage and environmental conditions. Follow this schedule because under-lubricating increases friction and wear, and over-lubricating can attract more dirt.
Replace Worn-Out Parts
A malfunction in your hardness testing equipment can cause downtime; scheduling a repair of the equipment leads to even more lost production days.
Some parts of the tester will require replacement. For example, the indenter on a Brinell equipment may wear out faster than other parts since it tests hard materials. During inspection, you’ll want to pay particular attention to this part.
Once a part is replaced, you’ll need a technician to calibrate the equipment to ensure accurate results.
Run a Test Verification
A test verification typically occurs when a part is replaced, like the scale or indenter, when you’re running a test on the day, and when there’s a shift or operator change. A verification is also in order when the readings you’re getting from testing your parts don’t fall within the acceptable range defined by your specifications or standards.
Hardness testers have an important job to do. With a broad range of applications across various industries, these testers must be maintained to ensure optimal performance. Follow routine maintenance, and your testers will deliver reliable results for years.
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