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Machine Guarding for Injection Molding Machines. OSHA 10-Hour Outreach Training Program for the Plastics Processing Industry A Presentation of the SPI-OSHA Alliance. (Screen Capture of Website). (Screen Capture of Website). Course Objectives.
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Machine Guarding for Injection Molding Machines OSHA 10-Hour Outreach Training Program for the Plastics Processing Industry A Presentation of the SPI-OSHA Alliance
Course Objectives • Identify the types of injuries that can occur while operating injection molding machines • Describe the possible causes of these injuries • Identify ways to safely operate injection molding machines • Recognize the importance of a total safety and health approach
Reasons to Focus on Injuries in the Injection Molding Process • High injury/illness rates • OSHA citations • National Emphasis Program • Site-Specific Targeting • High workers' compensation costs
Fatalities Amputations Avulsions Fractures Cuts and bruises Sprains and strains Burns Electric shock Types of Injuries
Some Causes of Injuries • Reaching around, under, over or through guards into hazardous areas • Removing or bypassing guards • Reaching into equipment to remove stuck or jammed material • Not using LOTO procedures • Machine/equipment malfunctions
Causes of Injuries(cont’d) • Lack of recognition of job hazards • Lack of familiarity with the equipment • Inadequate training, comprehension, or both • Operating machines with missing or inoperable guards and improper or inadequate machine maintenance
Injection Molding Machinery • Horizontal injection molding machine (HIMM) • Vertical injection molding machine (VIMM)
VIMMs • Combinations of vertical and horizontal clamp and injection configurations of machines • Regardless of the configuration of the machine, basic machine guarding and good safe work practices must be applied • Point of operation • Other moving machine parts
VIMMs: Unique Hazards and Issues • Gravity • Plastic splatter/missing insert • Flying inserts • Unexpected bystander interventions
HIMMs: Mechanical Hazards • Point of operation • Pinch points • Nip points • Rotating parts
Potential Injuries from Mechanical Hazards • Fatalities • Amputations • Avulsions • Crushing injuries • Fractures
Safety Guards and Devices • Types of guards and devices • Movable guards with interlocks • Fixed barrier guards • Presence-sensing devices • Mechanical safety bars • Locations of guards • Over/around moving equipment • Around electrical hazards • Around thermal hazards
Operator’s Gate • Equipped with redundant interlocks • Electrical • Hydraulic • Mechanical safety bar • Allows the machine to operate only when the gate is closed
Electrical Interlock • Allows the electrical system to operate and close the clamp • Actuated when the operator’s gate is opened or closed • Prevents clamp from closing when the operator’s gate is open
Hydraulic Interlock • Actuated by opening or closing the operator’s gate • Each hydraulic IMM requires at least one • Prevents clamp from closing when the operator’s gate is open
Hydraulic Interlock Operation After Activation Before Activation
Mechanical Safety Device • Prevents clamp from closing when the operator’s gate is open • Must have at least one mechanical device on all IMMs
Rear guard Top guard Parts discharge guard Feed opening guard Electrical system guards Purge guard Injection barrel cover Other Guarding
Rear Guard • Prevents clamp from closing when interlocked rear guard is opened • Should have at least two interlocks • Prevents access to mold areas
Top Guard • Required if employees can reach over the top of the machine and into hazardous areas • Should be interlocked if movable
Parts Discharge Guard • Keeps employees from reaching under the operator’s gate and into hazardous areas
Purge Protection • Covers the nozzle and purging area • In combination with PPE, minimizes exposure to molten plastic during purging • Window allows observation through purge guard, if equipped • Should be equipped with an interlock Purge guard Safety window Barrel cover
Injection Barrel Cover • Protects from exposure to high voltage and high temperatures
Grinder Guarding • Guarding by: • Enclosure over moving components • Anti-kickback flaps in feed throat • Proximity guarding – distance from feed chute to rotating knives Proximity Guarding
Abrasive Wheel Machinery Work rests on offhand grinding machines must be kept adjusted closely to the wheel with a maximum opening of 1/8-inch to prevent the work piece or tool from being jammed between the wheel and the rest, which may result in wheel breakage or wheel explosion.
Abrasive Wheel Machinery The distance between the wheel periphery and the adjustable tongue must never exceed 1/4-inch.
Power-Transmission Apparatus Unguarded belt and pulley Power-transmission apparatus (shafting, flywheels, pulleys, belts, chain drives, etc.) less than 7 feet from the floor or working platform must be guarded.
Presence Sensing Devices • Safety mat • Light curtain
Safety Guards and Devices Light Curtain
Presence Sensing Devices Safety Mat
How to Protect Yourself • Recognize the hazards in the job you are doing • Understand the requirements for guarding machines • Implement guarding solutions
Emergency Stop • Know: • Where it is located • What it controls • When to use it
Colors used with Safety Signs have meaning! DANGER White Lettering/Red Background WARNING Black Lettering/Orange Background CAUTION Black Lettering/Yellow Background
Robots • Used to automate repetitive or hazardous tasks • Must be guarded to prevent workers from entering or reaching into hazardous areas
References for Injection Molding Safety • ANSI/SPI B151.1- 1997 Horizontal Injection Molding Machines - Safety Requirements for Manufacture, Care and Use • ANSI B11.19-2003 Performance Criteria for Safeguarding • ANSI Standards are available at the following web site: www.ansi.org