Machine Guarding for Injection Molding Machines The Society of the Plastics Industry, Inc. A...

Machine Guarding for Injection Molding Machines

The Society of the Plastics Industry, Inc.

A Presentation of the SPI-OSHA Alliance


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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


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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


Types of Injuries

• Fatalities

• Amputations

• Avulsions

• Fractures

• Cuts and bruises

• Sprains and strains

• Burns

• Electric shock


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)


Vertical Injection Molding Machines VIMMs


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


Horizontal Injection Molding Machines - HIMMs


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


Electrical Interlock Operation


Hydraulic Interlock

• Actuated by opening or closing the operator’s gate

• Each hydraulic IMM requires at least one



Hydraulic Interlock Operation


Before Activation After Activation

Hydraulic Interlock Operation



• Must have at least one mechanical device on all IMMs

Mechanical Safety Device


Mechanical Safety Device Operation


Other Guarding

• Rear guard

• Top guard

• Parts discharge guard

• Feed opening guard

• Electrical system guards

• Purge guard

• Injection barrel cover


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


Top Guards (cont’d)


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


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


Signs and Warnings


Colors used with Safety Signs have meaning!

DANGER

White Lettering/Red Background

WARNING

Black Lettering/Orange Background

CAUTIONBlack Lettering/Yellow

Background


High Voltage


Rotating Screw


High Temperature


High Pressure


Robots

• Used to automate repetitive or hazardous tasks

• Must be guarded to prevent workers from entering or reaching into hazardous areas


The Robot


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


OSHA's Site-Specific Targeting (SST) Program

OSHA's Site-Specific Targeting (SST) program selects for inspection individual worksites with the nation's highest lost workday injury and illness rates based on data reported by more than 80,000 employers surveyed by the agency. In April of this year, OSHA announced that its site-specific targeting plan for 2006 would focus on approximately 14,000 worksites with higher than average injury and illness rates for unannounced comprehensive safety and health inspections over the coming year. The 14,000 identified sites are establishments located in stated covered by Federal OSHA.

This year's SST program will initially cover worksites that reported 6 or more injuries or illnesses resulting in days away from work, restricted work activity, or job transfer for every 100 full-time workers (known as the DART rate). The average national DART rate in 2004 for private industry was 2.5.

Over the past eight years, OSHA has used a site-specific targeting inspection program based on injury and illness data. This year's program stems from the agency's Data Initiative for 2005, which surveyed approximately 80,000 employers to attain their injury and illness numbers for 2004.


OSHA National Emphasis Program on Amputations

On March 26, 2002, the Occupational Safety and Health Administration (OSHA) announced a special national emphasis program aimed at reducing amputations in general industry workplaces. The National Emphasis Program on Amputations targets all types of power presses, including press brakes, saws, shears and slicers. This program is targeted to industries that are considered a high risk for operating equipment that can be very dangerous, as injuries involving these machines are often fatal or result in permanent disability. The plastics processing industry is among the industries under scrutiny for workplace amputations.

In keeping with OSHA's mission to identify and reduce or eliminate the workplace incidence of hazards which are causing or are likely to cause amputations, OSHA initiated targeted inspections of workplaces under SIC 3089, Plastics Products, Not Elsewhere Classified. These amputation hazard inspections began in April 2002. This is a Federal Emphasis Program. The twenty-four states and two territories which operate their own OSHA programs are encouraged, but not required, to adopt a similar emphasis program. The OSHA directive on this emphasis program is available on OSHA's web site under Regulations and Compliance, subcategory Compliance Directives, No. CPL 2-1.35.

Under this new initiative, regional and area OSHA offices will conduct outreach programs to identify, reduce and eliminate workplace hazards associated with these machines. Their programs will be conducted in three parts: outreach; targeting and selection; and inspection. Area offices will obtain and use additional data to identify and add establishments where serious injuries or fatalities related to these machines have occurred.


The Job Safety Analysis Process

The Job Safety Analysis (JSA) process is a very effective means of helping reduce incidents, accidents, and injuries in the workplace. It is a multi-step process.

•Basic Job Steps

•Potential Hazards

•Recommended Safe Job Procedures


Our sincere thanks to:

• United Southern Industries, Inc.

• OSHA Regions V & VIII

• OSHA's Office of Education and Training

• OSHA’s Salt Lake Technical Center

• Michigan OSHA

• The Society of the Plastics Industry, Inc.


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