The tough work required for the finishing process in foundry cleaning rooms can pose safety hazards to operators and anyone working in the area — especially when best practices are not followed. Unsafe practices can result in worker injuries and cost operations significant time and money.
That’s why it’s important to have a clear understanding about the abrasive products used in foundry cleaning rooms, and to understand the basic principles for safe and proper usage.
Safety in foundry cleaning rooms
There are several safety concerns that operators may encounter in a cleaning room. The grinders used to remove excess material from cast parts often have considerable weight to them, and operators may use the tools for an eight- or 10-hour shift — possibly more. In addition, for larger castings operators may have to bend over and maneuver around the part to grind it. These factors can result in operator strain and fatigue.
It’s also common for cleaning rooms to have numerous operators working within a few feet of each other, which can pose safety risks if grinding is not done properly.
The repetitive vibration of the tool is another safety issue that operators must contend with: The vibration can cause operator fatigue that can lead to mistakes. Improper use of a tool or abrasive product also may cause the abrasive to come apart and send debris flying at high speed.
Personal injury to the tool operator or others working nearby is the chief concern, but there are other consequences of unsafe tool and abrasive use. It can shorten the abrasive life, increase downtime for product changeover and lower productivity.
Tips for safe abrasive use in foundry cleaning rooms
Following some best practices — no matter what tool or abrasive product an operator is using — can help to address safety concerns.
• Match the product and tool rating. Be sure the abrasive product has an rpm rating that meets or exceeds the rating of the tool. Otherwise, there will be a risk of over-speeding the product and the potential for failure that could cause injury. Be aware that some of the smaller abrasive products designed for foundry applications come in various sizes that have different rpm ratings for different tools.
• Use the proper guards. Using the tool guard — and making sure it’s the right guard for the product — is important for safety. Many grinders are not supplied with the correct guard that is required by ANSI guidelines for a specific product. Type 11, Type 27, and Type 1 guards are all different, so be aware of which one is necessary for the product and abrasive being used. Some operators may forgo the guard, especially if they are working in many angles and positions and do not want to continually adjust the guard. This is an unsafe practice that can result in injury.
• Wear the necessary PPE. The nature of the work in foundry cleaning rooms requires personal protective equipment (PPE), including a face shield, proper gloves, steel-toed shoes with metatarsal protection, leather aprons, and fire-resistant clothing.
• Mount the product correctly. Be aware of any mounting recommendations for specific products. For Type 11 cup wheels, for example, ANSI specifies using a non-relieved flange and depending on the cup size, the washer will vary in diameter and thickness. Also be sure to always disconnect power to the tool before making a media change.
• Stay on top of tool maintenance. Certain parts on a tool can wear out with use, so be sure to check the tool regularly and make time for maintenance. Using the tool as it has been designed also can help extend maintenance intervals.
• Choose the right tool and abrasive for the job. If the finishing job requires working in small spaces, avoid using oversized products. Jamming a larger wheel into a small space can cause product failure, since the wheel wants to keep moving and may kick back if there is no room for it to spin.
Best practices for specific product types
There are many different abrasive products in service in foundry cleaning rooms. Be sure to understand which product is best-suited to each job, and how tips for safe usage may vary according to the product type.
Type 27 grinding wheels. When using grinding wheels, the angle of presentation to the part should be zero to 45 degrees. Using an angle that is too steep may cause gouging or undercutting of the workpiece. To optimize grind rate and product life, avoid pushing too hard.
Look for a Type 27 grinding wheel designed with anti-chipping technology, which has edges that are more durable and improves safety by reducing the risk of high-energy debris being emitted during grinding.
Type 11 flaring cup wheels. Cup wheels should typically be used at a 15- to 25-degree approach to the part. They can be used flat when working on a larger surface area.
Avoid rocking the grinder back and forth when using a flaring cup wheel because the backside of the wheel could catch and pull the operator’s arm. Always use the face of the wheel and not the side of the flared cup.
Cones and plugs. Cones and plugs are typically used on an air grinder, and unlike most other abrasive products, they do not require a safety guard. Always grind on the front outer diameter of the abrasive. Avoid grinding with the middle or back of the abrasive as this can prematurely wear out the product and cause it to fracture. Avoid grinding with the tip because the product will be hard to control.
Cones and plugs are not reinforced, so operators should take care to not apply excessive pressure that potentially could cause product breakage.
Snagging wheels. Type 1 snagging wheels use a guard that covers the wheel on both sides, for 180 degrees of coverage. As a result, very little of the wheel is exposed, which protects the operator in case of breakage.
Be sure the arbor hole is the right size for the grinder to which the abrasive wheel is mounted. Also, never set down a snagging wheel while the wheel is still spinning. Because of the orientation of the wheel on the tool, setting down a spinning wheel will send it across the floor or table very quickly.
Mounted points. Mounted points are used on high-speed grinders and are very small compared to other products used in foundry cleaning rooms. Because they’re not reinforced, avoid applying too much pressure to mounted points – because they can break easily.
All these abrasive products are available in various material types and size options. Choosing ceramic abrasives for Type 11 cups, Type 1 snagging wheels, and cones and plugs can deliver higher removal rates, which helps to minimize operator fatigue and potential injury.
Choosing the right abrasive technology
Look for abrasive products that are precision-balanced to reduce vibration and help minimize repetitive motion injuries. The wheel will grind easier and vibrate less. Type 11 cup wheels that are precision-balanced offer a substantial reduction in product vibration versus competitive products, which reduces operator fatigue during prolonged use.
Also, the mounting nut for abrasives is an important factor for minimizing product failure. Recently Weiler® redesigned its mounting system for cup wheels, doubling the torque holding strength and speed burst rating compared to the traditional cap-style mounting systems, to make operation of these products safer.
Choosing the right tool and abrasive product for the job can help to overcome the toughest cleaning-room challenges. And paying attention to best practices and safe use of abrasive products can help to minimize operator fatigue and injuries, while also saving time and money.
Rick Sawyer is the OEM & technical business development manager, and Kyle Thompson is the technical product manager – both with Weiler Abrasives.