Does your metal fabrication operation have issues with running overtime on production or falling behind on deliverables? Perhaps labor challenges are causing issues with bottlenecks or slowdowns. All these factors can be affected by the grinding efficiency in your operation. When grinding isn’t being done as efficiently as possible, it can cause a traffic jam that slows down your entire production process.
Think about what even a 10 percent improvement in grinding efficiency could mean for your overall operation. Having more labor hours could help you eliminate overtime or improve throughput – almost like hiring another employee.
Working with an expert can help determine exactly how much time and money your operation spends on grinding, finishing and cleaning – which, in turn, can help you find improvements that save time and reduce costs.
Grinding efficiency
In many operations, grinding efficiency is often overlooked, especially when there are no obvious problems with it. But inefficiencies in grinding can result in delays or time lost across the rest of the production facility.
Some of the most common mistakes that can reduce grinding efficiency include:
- Choosing the wrong abrasive for the job: Sometimes, operations have used the same grinding wheel for years without looking at data or considering other options. But, using the wrong abrasive product for the work being done can result in less-effective performance and shortened abrasive life – both of which add more labor time to complete the work and more frequent product changeover. This added time may also cause you to miss quality or productivity goals and increase operator fatigue – and the risk for injury.
- Using a less-expensive, low-amp grinder: Choosing the right abrasive is key, but a product can only work as well as the tool on which it’s used. A low-amperage grinder may not have enough power to push a grinding wheel that has a hard bond, for example. This leads to wheel loading and poor performance (reduced efficiency) and operators may throw away the wheel sooner (increased consumable costs).
- Using the wheel incorrectly: How the operator uses the grinding wheel also plays a role in efficiency. Using too much pressure can damage the workpiece and increase scrap, which significantly increases production time and costs. Excessive pressure can also increase operator fatigue and the potential for injury. The pressure being used often ties back to the abrasive product choice. If the wrong abrasive is chosen, the operator may push harder to get better performance. Excessive wheel vibration can occur when the product is being used incorrectly or the wrong product is chosen. Wheel vibration also adds to operator fatigue, which can impact employee turnover and retention.
Evaluating value
What is the value of grinding in your facility right now? Many facilities don’t know or have never put a dollar or time amount on it. Longer product life that results in reduced grinding wheel costs is nice, but a reduction in labor thanks to increased efficiency can have a much bigger impact because labor is the largest cost in any grinding operation. Labor time saved translates into greater productivity, which is paramount if your goal is to get more product out the door, even with fewer people.
Working with experts to analyze and determine abrasive costs and efficiency can help operations understand exactly how much their grinding process costs and where gains can be found.
While it’s easy to purchase products based solely on price, that choice potentially compromises safety, performance and productivity. To find real cost savings, facilities must test and evaluate abrasive products to select ones that will allow them to reduce cycle times, save dollars and guarantee better results.
The Weiler Consumable Productivity (WCP)program collects hard data around how abrasive products are used, how long they last and how productive they are. The program looks at the entire process – everything from your abrasive and labor costs to the time spent on grinding and the material removal rate – and effectively compares several products to determine the best product for an application.
The right products
Evaluating the efficiency of the grinding operation and then making a change to the abrasive product being used can make a significant difference. This change could involve a switch in the type of product being used – moving from a grinding wheel to a flap disc, for example – or to the abrasive grains being used, such as switching from zirconia alumina to ceramic.
If a grinding wheel has always been used, changing to a flap disc may provide faster cutting in some applications, and a resin fiber disc may offer even more speed and faster cutting. But a resin fiber disc won’t last nearly as long as a grinding wheel, so the right choice depends on the goals of your operation. When it comes to abrasive grain retention, a softer bond breaks down faster, but tends to be preferred by operators because it feels smoother and is more comfortable to use.
It’s important to look at the entire application – including before and after the grinding process – to choose the right abrasive product.
Optimizing performance
Once the abrasive product is chosen, how can you maximize grinding performance to ensure you’re getting the efficiencies you planned on? Following best practices and using proper technique can help optimize results. Here are some tips to keep in mind:
- Start with a backstroke: Always start to grind with a backstroke before pushing forward. This helps break in the grinding wheel and reduces the chance of gouging the base material or getting wheel kickback that can result in operator injury.
- Don’t exceed speed or size recommendations: The speed rating of the abrasive product should always meet or exceed the speed rating of the tool on which it is used. The wheel size should also match the size of the tool.
- Use appropriate pressure: Proper pressure is critical with any abrasive product because heat is the enemy of an abrasive. Using more pressure than necessary produces more heat, which breaks down the wheel faster and potentially causes product loading.
- Watch the orientation: Holding a Type 27 grinding wheel at a higher angle, such as 35 degrees, results in a faster cut, but this angle also reduces wheel life. Grinding at an orientation of 10 degrees to the workpiece helps extend wheel life.
- Keep the wheel in motion: Don’t dwell in one spot too long, which can cause heat to build up. Move the wheel back and forth, almost like a sawing motion, with two hands on the grinder. Also, when the operator engages their hips and lower body in this motion, it helps release stress in the neck, shoulders and arms to avoid injury.
- Choose the right abrasive product for the material: When grinding aluminum, a wheel that isn’t designed specifically for that material will load quickly and reduce performance. Instead, buy an abrasive product designed for aluminum.
- Use products as designed: If you’re grinding and cutting, be aware that some wheels are designed to do both tasks while others are not. Look for markings on the wheel that designate if it’s for grinding only or can be used for cutting and grinding. It’s hazardous to use a wheel for a job for which it isn’t designed.
It’s important to always read the recommendations and safety information for any grinding wheel to get the best results. Also, keep the tool guards in place and use them properly to enhance operator safety.
Inefficiency in the grinding operation can be a much bigger expense than many operations realize. Analyzing how much time and money your grinding products and processes cost can help you choose the right solutions for your application. In addition, training operators to use abrasive products to their full potential is critical to overall efficiency and safety.
