March 2020 Issue
Toc

Several persistent problems sap the productivity of metalworkers who use angle grinders and bonded abrasives in their daily work. Lack of grinding comfort, poor grinding wheel performance, excess fatigue from low-quality tools, and noise and vibration are all on the list of common yet serious problems. Such problems harm productivity and can drive up costs.

Grinding is among the most demanding jobs in metalworking due to noise, vibration and dust, which all lead to operator stress and fatigue.

At a glance, it seems few proven methods exist to drive down labor costs when it comes to the use of bonded abrasives in the metalworking industry. But this is not necessarily the case. As with any industry, trends drive demand. Within the metalworking sector, and with regard to bonded abrasives in particular, demand for comfort has emerged as a more pronounced tendency among workers who seek high-performance grinding tools that don’t require them to sacrifice safety or ergonomically advanced working methods.

So, how do we reduce labor costs by enhancing comfort? To answer this question, it is important to define what a comfortable abrasive is. Put into context, a sharper picture emerges as to how and why productivity can be increased with a premium bonded abrasive. A comfortable abrasive is one that:

  • Requires minimal pressure on the grinder for maximum material removal
  • Minimizes dust generation from raw materials
  • Is durable with exceptional integrity; consequently, less dust is generated
  • Minimizes vibration and noise transmitted to the operator during grinding

Comfort Is Key

A grinding wheel that minimizes the transmission of vibration helps reduce operator fatigue. This means the operator can work longer and safer. Premium bonded abrasives deliver fast and aggressive removal rates. When paired with a powerful grinder, they minimize the pressure the operator needs to apply to a workpiece, which results in a comfortable grinding experience. This enables the operator to work longer in what would typically be a tiring physical position. This can ultimately reduce operation time, which itself is a gain in productivity.

Walter’s Xcavator XX ceramic grinding wheels allow for a fast metal removal while increasing operator comfort.

Additionally, a premium grinding wheel minimizes dust, which is partly due to high heat-resistant bonding agents that help maintain wheel integrity. This not only enhances safety – excess dust is an eye irritant and respiratory risk – but comfort, too.

The cost of grinding abrasives typically represents 15 percent of the total cost of a metalworking project. Cutting the cost of consumables through a “lowest cost” purchasing approach can be tempting, but it is short-sighted because productivity (where the remaining 85 percent of spending must be disbursed effectively and strategically) will inevitably diminish over the long term. This is because while cheaper products may offer direct savings, their inferior quality will drive up replacement costs over time. Many problems are often linked to low-quality grinding wheels, including a need to apply excess force; premature wheel wear; and excessive vibration, noise and dust.

The inescapable consequences of working with lower quality abrasives generally fall into two areas in which they inevitably have a significant impact: productivity and health and safety.

A low-quality grinding wheel implies many things: low-quality bonding agents and abrasive grains and low tolerances for wheel unbalance, among others. The wheel may cost less, but these factors add up to a wheel that is simply not durable and, as a consequence, will harm productivity. In short, a low-quality wheel with poor durability can lead to:

  • Increased wheel consumption, which drives up costs
  • Increased wheel changeovers, which adds process steps and reduces productivity
  • Excessive dust, which increases the risks of respiratory diseases and eye irritation
  • Poor aggressiveness, which means slow removal rates and increased operation time
  • Poor aggressiveness also means the operator compensates by adding wheel pressure, which quickens the onset of fatigue and can result in muscle cramps and long-term pain
  • Safety hazards because low-resistance wheels can explode and risk serious injuries
  • Injured workers, which can result in reduced general workflow efficiency, expensive health and safety reviews, and even legal proceedings
Demand for comfort has emerged as a more pronounced tendency among workers who seek high-performance grinding tools that don’t require them to sacrifice safety or ergonomically advanced working methods.

Safety Factors

Enhanced comfort is critical from multiple standpoints. Although a handful of players in the metalworking industry have made impressive technological and product advances in the past decade, grinding remains a challenging and physical form of work that can take its toll on the health of a worker over time. When looking to reduce labor costs, it is important to look at the wider picture of health and safety implications and how they relate to worker performance.

Double-reinforced grinding wheels are stronger because the reinforcement ensures integrity.

The consequences of working with low-quality abrasives can become painfully obvious in terms of reduced productivity, yet the risks to health and safety cannot be ignored for a host of other critical reasons. Manufacturing, trade and equipment operators are among the most dangerous occupations. In fact, workplace injuries are on the rise, according to the Association of Workers’ Compensation Boards of Canada. In 2017, the latest year for which data is available, injured workers made 251,625 lost-time claims, up 4.5 percent from 240,682 in 2016. The story is similar in the United States where workplace injuries cost American companies more than $1 billion per week, according to insurer Liberty Mutual.

In terms of bonded abrasives, strict industry performance and safety benchmarks have long been in place. All abrasives are subject to manufacturing standards to ensure their integrity and safety in the hands of operators. In North America, this is governed by ANSI B7.1 Safety Requirements for the Use, Care and Protection of Abrasive Wheels. The European standard, EN 12413, is even stricter in terms of safety and performance requirements for bonded abrasives.

One area that is critical to grinding wheel performance – and by extension user comfort and safety – is wheel balance. Consider a wheel that is slightly thicker on one side. Though not visible to the naked eye, the thicker side is slightly heavier. At a testing speed of 10,000 rpm, an unbalanced wheel generates excessive vibration. Excessive and prolonged vibration can pose serious health risks for metalworkers.

Unfortunately, exposure to excessive vibration increases the risk of hand-arm vibration syndrome (HAVS), a painful condition that can become permanent. HAVS has a high prevalence in industries such as construction, mining, forestry, foundry work, vehicle assembly and metalworking trades.

Some jurisdictions impose vibration exposure limits, but not all. In Canada, the Centre for Occupational Health and Safety sets out guidelines on tool vibration measurement, controls and standards. For its part, the European Union has regulated exposure to hand-arm vibration since 2002. In the United States, ANSI issued a voluntary standard based on the EU Directive, which imposes two limits that relate to the amount and intensity of vibration workers can be exposed to daily.

However, it is underdiagnosed. In Canada, there are an estimated 72,000 to 144,000 cases of HAVS, according to the College of Family Physicians of Canada. In the United States, as many as 10 million people are exposed to occupational vibration daily, according to occupational vibration experts Donald Wasserman and Howard Mason. About two million U.S. workers are exposed to hand-arm vibration, and as many as half will develop HAVS, according to Wasserman, who is also a biomedical engineer. Other experts believe the number to be higher because HAVS is sometimes confused with carpal tunnel syndrome, a similar condition that is associated with vibrating tools and work that requires a strong grip.

Durable wheels reduce time-consuming wheel changeovers, which helps reduce operation time.

Premium Productivity

Premium bonded abrasives may cost more than other products but, given their high quality, the fact that they enhance productivity is virtually irrefutable. Consider the following factors:

  • Premium abrasives are made from high-quality abrasive grains. Sharp and resistant to wear, they provide perfect balance between aggressiveness and durability.
  • All grinding wheels come with strength built in – in the form of fiberglass reinforcement. But, premium wheels have thicker fiberglass and sometimes even extra layers. Double-reinforced wheels are stronger wheels for the simple reason that the reinforcement acts as the skeleton of the wheel and ensures integrity.
  • Premium bonding agents are resistant to heat and mechanical energy and are low in water content. Better bonding agents contribute to longer wheel life.

Each of these aspects enables a premium grinding wheel to deliver a high removal rate with lower operator pressure. That in itself will reduce operator fatigue and facilitate longer work cycles with fewer stoppages. Therefore, operation time will decrease and productivity will increase.

Another important advantage that premium bonded abrasives bring to the shop floor is durability and, consequently, longer wheel life. Durable wheels reduce time-consuming wheel changeovers, which helps reduce operation time. Meanwhile, reduced product consumption equates to lower product inventory, which helps keep costs down.

While premium bonded abrasives may cost more, they deliver enhanced worker comfort, stronger performance and higher levels of safety, which over time, can offset elevated expenditures by driving productivity. Taking the lowest cost approach to purchasing undermines efforts to drive down labor costs because low-value products often equate to low quality, which undermines productivity in myriad ways.

The drive to develop and improve premium bonded abrasives – tools that address metalworkers’ actual needs for durable, comfortable, high-performance, safe and ergonomically intelligent products – can only succeed in driving labor costs down if we continue to listen closely to tomorrow’s shop floor problems and act nimbly to deliver practical solutions.