Three steps to increasing productivity with grinding

With demand for metalworking applications to increase productivity, one area that is often overlooked, but can make a vast difference is the tools that are used. Manpower and abrasives together account for approximately 90 per cent of the total cost of grinding with handheld tools. It is therefore essential that steps should be taken to reduce time to complete each grinding task to increase productivity and cost savings. Ensuring that tools are operating to the right speed and removing material at the optimal rate are vital to operating efficiency.

For each material removal job, such as chamfering a steel plate, deburring a casting, or smoothing a weld seam, there is a specific abrasive need. Based on the application, carbide burrs, bonded wheels and coated pads, wire brushes, polishing pads or many others could be required. The rate of material removal is affected by the tool’s ability to run and maintain the abrasive at the right speed.

Key to achieving an optimal material removal rate is a well-working tool. There are a number of steps to take to ensure they are set up correctly for the application. This may be through making sure the grinders have appropriate features for the job such as an air governor or autobalancer, as well as making sure there is a good maintenance regime in place.

1. Air governors

The optimal abrasive's speed can be achieved by equipping the tool's air motor with a governor. An air governor acts like a “cruise control” for the grinder: it adjusts the air flow to the load applied on the tool, so the abrasive maximal speed is maintained, maximizing the material removal.

The governor limits the air flow through the motor when no torque is applied. As soon as the operator increases his feed force while working on the application, the air governor allows more air to flow through the air motor, maintaining the rotational speed of the abrasive. With this design, the abrasive is run at the correct speed and delivers maximal material removal.

If a tool is not equipped with an air governor, as soon as feed force is applied, the tool’s speed decreases, and therefore, the abrasive cannot run at the right speed. The operator needs more time to get the same job done.

2. Autobalancers

Another consideration is choosing a grinder with an autobalancer, which stabilizes the tool, and is considered one of the best anti-vibration options. It is a disk, such as ball bearing with freely moving balls inside, that is fixed onto the output of the tool as a flange, and spins at the same speed as the tool’s output. Thanks to the weight of the spinning balls, this mechanism gives a gyroscopic effect and balances the tool, greatly reducing any vibration.

The tools’ lifetime is enhanced as they have shorter trigger times, and abrasive disks last longer because the contact between the abrasive and the application is optimized. This increases the material removal rate up to 15% compared with using a tool without an autobalancer, which results in fewer disks – and therefore the associated cost – required to finish the job.

3. Maintenance

Maintenance is the final consideration. It’s vital to carry out routine maintenance on all tools to ensure they are kept in excellent working condition. Afterall, pneumatic tools are mechanical systems comprising wear parts that needs regular inspection and changes (as required). The parts that wear most frequently and need regular maintenance are:

Blades, with inspection recommended every 500 h

Bevel gear (angle grinders and sanders only), with the maintenance interval specified as every 1000 up to 2000h, depending on the tools.

Ultimately, by having a good setup, the tool will work well to a high performance, you will be able to remove more material, which enables you to save time and operate most efficiently.

For more information on improving efficiencies in grinding read Chicago Pneumatic’s Expert Corner Improve your productivity with governed air motors or visit www.cp.com