Electrically powered milling machines cut metal using a rotating cutting device called a milling cutter. These machines cut flat surfaces, angles, slots, grooves, shoulders, inclined surfaces, dovetails, and recessed cuts. Cutters of different sizes and shapes are available for a wide variety of milling operations.
Milling machines include knee-and-column machines, bed-type or manufacturing machines, and special milling machines designed for special applications. Typical milling operations consist of selecting and installing the appropriate milling cutter, loading a work piece on the milling table, controlling the table movement to feed the part against the rotating milling cutter, and calipering or measuring the part.
The following procedures are frequent causes of amputation from milling machines:
§ Loading or unloading parts and calipering or measuring the milled part while the cutter is still rotating.
§ Performing servicing and maintenance activities such as setting up the machine, changing and lubricating parts, clearing jams, and removing excess oil, chips, fines, turnings, or particles while the milling machine is either stopped but still energized, or while the cutter is still rotating.
§ Getting jewelry or loose-fitting clothing entangled in the rotating cutter.
| Case History | An employee was using a milling machine to cut metal samples to length. After a part had been cut, the employee needed to gauge the part size. While he was checking the edge of the sample, the blade caught the tip of his glove, pulled his hand into the cutting area, and amputated his right ring finger and part of his middle finger. Source: OSHA IMIS Accident Investigation Database |
You should implement the following engineering, work practices, and administrative controls:
§ Install self-closing guards that enclose the milling cutter when the table has been withdrawn.
§ Install an interlocked barrier guard around the table. When equipped with a cutter blade brake, the brake should be applied when opening or removing the interlocked barrier guard.
§ Use other safeguarding devices such as splash shields, chip shields, or barriers if they provide effective protection to the operator and when it is impractical to guard cutters without interfering with normal production operations or creating a more hazardous situation.
§ Instruct operators not to use a jib or vise that prevents the point of operation guard from being adjusted appropriately.
§ Develop and implement safe work practices for machine operators and conduct periodic inspections to ensure compliance.
§ Ensure that all operators receive appropriate on-the-job training by experienced operators until they can work safely on their own.
§ Instruct operators to move the work holding device back to a safe distance when loading or unloading parts and calipering or measuring the work and not to perform these activities while the cutter is still rotating unless the cutter is adequately guarded.
§ Prohibit operators from reaching around the cutter or hob to remove chips while the machine is in motion or not de-energized.
§ Instruct operators to remove fines, turnings, or particles only with a brush while the cutter is stopped.
§ Instruct operators to place the jib or vise locking arrangement so that force must be exerted away from the milling cutter.
§ Instruct operators not to leave the cutter exposed after withdrawing work piece.
§ Instruct operators to turn off the milling machine when not in use or when left unattended for any period of time.
§ Instruct employees not to wear gloves, jewelry, or loose-fitting clothing while operating a milling machine and to secure long hair in a net or cap.
§ Instruct operators to perform servicing and maintenance activities under an energy control program in §1910.147.
No comments:
Post a Comment