The Society of the Plastics Industry. Inc. (SPI) and OSHA formed an Alliance in the fall of 2002 in order to help employers in the plastics industry provide safer working environments in their plants. This is a national Alliance, signed with Federal OSHA. As you may know, there are 22 State Plan States that run their own occupational safety and health programs for general industry employers. The rest of the states are covered by Federal OSHA. Although most of the State Plan States have adopted the Federal OSHA Standards, there may be some differences (e.g., California, Michigan). This course is based on Federal OSHA standards. This course on Machine Guarding and Lockout/Tagout (LOTO) was created by a dedicated team, consisting of experts from OSHA and industry. This is a train-the-trainer course—that is, these training modules not only consolidate all the critical information you need on machine guarding and LOTO, but also prepare you to train employees at your worksite. The Alliance would like to hear back from you—not only about how well these tools work for you and how many people you train, but also about ideas you may have for other areas that we can work together on to make a safer workplace in our industry. Please send your comments to Susan Howe, SPI, 1667 K Street, N.W. Suite 1000, Washington, D.C. 20006 or via email at firstname.lastname@example.org. Thank you. Fourth Edition – September 2008
Our Alliance developed a Web site to provide you a central resource for safety and health information about the plastics industry. You can link to this site at: http://www.osha.gov/SLTC/plastics/index.html This and the other associated pages are a valuable resource for developing your training program, locating information, and learning how-to’s to provide a safer work environment for your employees.
This site contains links to the machine safety training programs developed by our Alliance. You can link to this site at: http://www.osha.gov/SLTC/plastics/otherresources.html
This course addresses machine guarding and lockout/tagout safety issues relating to plastics injection molding machines. It does not cover everything you need to know about plant safety. You’re going to hear a common thread running through this course. Machine safety and lockout/tagout programs are only part of the effective safety and health management system at your plant. You should use OSHA&apos;s Safety and Health Management eTool, http://www.osha.gov/SLTC/etools/safetyhealth/index.html, with what you will learn in this course, to develop, refine, or improve your company’s goals for addressing safety and health in your workplace. Additional information on Machine Guarding requirements can be found at the following site: http://www.osha.gov/SLTC/machineguarding/index.html Additional information on Lockout/Tagout requirements can be found at the following site: http://www.osha.gov/SLTC/controlhazardousenergy/index.html
One of the tools developed through our Alliance is a Machine Guarding eTool for Plastics Machinery. OSHA&apos;s eTools are &quot;stand-alone,&quot; interactive, Web-based training tools on occupational safety and health topics. They are highly illustrated and utilize graphical menus. OSHA&apos;s Machine Guarding eTool has modules on saws, presses and plastics machinery. You can access these eTools at the following site: http://www.osha.gov/SLTC/etools/machineguarding/plastics.html Use the following site to go directly to the Plastics Machinery Machine Guarding eTools: http://www.osha.gov/SLTC/etools/machineguarding/plastics.html
Plastics is one of the largest manufacturing industries in the US. We directly employ over 1.1 million workers. And plastics processors are the second most frequently cited industry under OSHA&apos;s lockout/tagout standard and the third most frequently cited industry under OSHA&apos;s machine guarding standards. Citations for the year October 2006 - September 2007 are listed below. For Lockout/Tagout - 1910.147 #Cited #Insp $Penalty Industry Classification 183 109 $161,130 SIC Code 3089 For Machine Guarding - 1910.212 #Cited #Insp $Penalty Industry Classification 133 110 $171,693 SIC Code 3089 Information about OSHA&apos;s Site-Specific Targeting Program (SST) is at the end of this presentation, along with reference materials on OSHA’s National Emphasis Program on Amputations.
These are some of the common injuries that occur in the plastic processing industry. We are focusing today on the more severe injuries—those in the left column. Fatalities, obviously, are the most severe of all. Amputations can disable and disfigure. Avulsions should be considered a near-miss to amputations. Fractures occur when employees are involved in a crushing or caught-in hazard. Employees receive burns from hot equipment and from hot plastic.
Never attempt to reach around, under, over, or through a guard. If a person standing on the floor can reach over the machine or machine guard into the point of operation, either install new guarding or modify the existing guarding to prevent that from occurring. One common approach is to install a top guard that is either fixed or interlocked, depending on the need for access to the area. Never remove, alter, or attempt to otherwise bypass a safety interlock. Do not remove or open a fixed guard for normal operating tasks. Provide training on the hazards and safety features of the plastics injection molding equipment for all employees who may come in contact with it. We will discuss LOTO requirements in the second half of the program
Speaker should paraphrase the points listed on the slide. This would be a good time to engage the audience in discussing specific &quot;events&quot; (such as, near misses) that have happened to them or in their work place.
Injection molding is the method of forming objects from granular or powdered plastics in which the material is fed from a hopper to a heated chamber in which it is softened, after which a ram or screw forces the material into a mold. Pressure is maintained until the mass has hardened sufficiently for removal from the mold. Injection molding machines are available in a broad range of sizes. They are normally rated by their maximum clamping force, with normal ranges from about 25-150 tons for &quot;small&quot; machines, 150-750 tons for &quot;medium-size&quot; machines, and 750-5000+ tons for &quot;large&quot; machines.
We are covering both horizontal and vertical injection molding machines today. We are going to begin by highlighting the unique hazards and issues associated with VIMMs in the next two slides. In spite of these unique hazards and issues associated with VIMMs, the safe operating practices and procedures apply to both types of machines.
Gravity presents a unique hazard associated with vertical injection molding machines. Examples include hydraulic line or linkage failure that could cause the movable platen to fall. Plastic splatter can occur when an insert is missing or misplaced. Example would be failure to place a spoon insert into the mold cavity when the handle is being molded around the spoon insert to make a finished spoon. The missing insert creates an opening that allows plastic to shoot out from the mold and splatter. Improperly placed inserts can be caught between the mold halves and ejected under great force. The guarding protects the operator but not necessarily other people who might unexpectedly reach into hazardous areas.
Now we will discuss safety issues related to horizontal injection molding machines.
The point of operation is the area where the work actually occurs. Pinch points can occur where a moving surface comes in close proximity to a stationary surface, and a crushing hazard is created. Examples include: Nip points in the injection molding machine include chains and sprockets, belts and pulleys, and gears. Although not part of the injection molding machine, nip points can occur due to mechanisms and motions of mold components (such as core pulls, unscrewing devices, sliding cams, sliding cores, sprue pickers) and auxiliary equipment. Rotating parts that might pose a hazard include pump shafts and couplings, die height adjustments, and rotating screws.
These are the injuries that can occur if the machinery is not guarded, or the employee defeats, by-passes or reaches over, under, around or through the guarding into the Point of Operation. Avulsion is a ripping away of the flesh that does not include bone loss. An example might be where your finger gets caught in a nip point, you pull it out, and flesh is torn off, but the bone is still there. It’s impossible to see the scale in this picture, to be able to tell how big a body part can fit in this space, but you should know that IMMs come in many sizes, from small enough to fit on a tabletop to large enough to produce a whole car body. Depending on the particular machine, these potential injuries might be to a finger, arm, head, or entire body.
Employers are responsible to ensure that machinery is ordered with adequate guarding or retrofitted to protect employees from exposure to mechanical, electrical, and thermal hazards. This module contains a reference section listing some ANSI Voluntary Industry Consensus Standards that you may want to consult as you devise your machine guarding. Newer US-made machines are usually compliant with ANSI machine safety standards, but please note that many older machines have not been retrofitted with updated safeties. In addition, foreign-made machines may not meet all US safety requirements. When purchasing, leasing or using injection molding machines, it is your responsibility to ensure that they are in compliance with all appropriate safety standards.
The operator&apos;s gate allows the operator access to the mold and should be equipped with interlocks (such as electrical, hydraulic, and mechanical) that allow the machine to operate only when the gate is closed. Do not attempt to override any of the interlocks or to reach over, under, around, or through the operator&apos;s gate (or other guards) while the machine is operating.
The electrical interlock prevents the mold from closing when the gate is open.
This animation shows the operation of an electrical interlock. Proper operation of the electrical interlocks should be verified on a regular basis specified by the machine manufacturer, maintenance department, or safety director.
The hydraulic safety interlock valve prevents the clamp from closing when the operator&apos;s gate is open.
This animation shows the operation of a hydraulic interlock. Proper operation of the hydraulic interlocks should be verified on a regular basis specified by the machine manufacturer, maintenance department, or safety director.
This slide shows the operation of a hydraulic interlock before and after activation. Proper operation of the hydraulic interlocks should be verified on a regular basis specified by the machine manufacturer, maintenance department, or safety director.
The mechanical safety device physically prevents the mold and clamp from closing when the operator&apos;s gate is open.
This animation shows the operation of a mechanical safety device. Proper operation of the mechanical safety device should be verified on a regular basis specified by the machine manufacturer, maintenance department, or safety director.
We will discuss these typical types of guarding equipment in the next few slides. Depending on the complexity of your process, your machinery may have more guarding than what is pictured in this course. Regardless of how specialized, or how simple your manufacturing processes are, employees must be protected from all hazards.
The movable rear guard should be equipped with at least two interlocks that stop clamp motion when the guard is open. This guard should only be opened for setup and maintenance activities. Use the front operator&apos;s gate for operator access to the mold space.
On low profile machines, a top fixed guard should also be installed. This prevents a person from reaching over the top of the machine. The majority of molding machines do not require this guard, as they are approximately 9 feet tall. Guards that are removed only for maintenance, and that require tools to be removed do not need to be interlocked.
Additional examples of top guards.
A guard should be placed at the opening for parts discharge to prevent an employee from reaching under the operator&apos;s gate and into the mold area. A chute, conveyor, or other object can take the place of a guard attached to the machine if it prevents access to this area.
The injection unit can also be controlled via guards. The ANSI/SPI B151.1-1997 Standard for HIMMs requires guards to protect the front, rear and top of the purging area. An electrical interlock insures that the guard is in place during the automatic running of the machine or during the purging cycle. Should viewing of the purge area be necessary, a window should be provided that will withstand the splashing of the plastic material without failure. The purge shield covers the nozzle of the injection molding machine and helps to prevent burns from molten plastic material inside the injection system. The operator may monitor the purging area through the window in the purge shield. Injection unit operation proceeds while the purge shield door is closed, but is interrupted when the door is out of position. Heater Band Shield This metal guard cover the barrel and heater bands. It must be in position when power is on and/or the machine is in operation. Heater band terminal ceramic covers insulator caps should be maintained in good condition. If contact is made with any bare terminal while the power is on, electrical shock may result. Severe burns may also result if contact is made with hot metal surfaces or heater bands. Never stand on this shield, as it is not designed to bear weight.
The barrel cover acts as a barrier to block access to the injection unit to prevent contact with high voltage and high temperatures.
During normal operation the point of operation of the granulator (grinder) is guarded from access by both fixed and interlocked guards. Many accidents associated with this piece of equipment occur during cleaning operations due to direct access to the cutting knives, both rotary and stationery, that must be cleaned and inspected during changeovers of material type or material color. During cleaning the rotor and flywheel, the mechanism must be turned manually to access all of the areas that need cleaning. Inertia of these heavy components lends to injuries including cuts, bruises, and amputations.
1910.215(a)(4) The purpose of the guarding is to prevent tools from coming between the work rest and the grinding wheel.
1910.215(b)(9) If the wheel should break, the upper guard prevents wheel fragments from flying back at the operator.
1910.219 Even if the apparatus is 7 feet or more from the floor or working platform, if employees need to access the space, it must be guarded or locked out. Some ANSI standards specify 8 feet; consult current standards.
Examples of presence sensing devices include: safety mats, interlocked platforms, photo-electric beams, or other similar devices. Safety Mats: The operation of the safety mat is easy to understand. The safety mat is a simple, normally open switch. When a specified minimum weight is applied to the safety mat the &quot;switch&quot; closes. This sends a signal to the safety mat controller, which in turn, sends a stop signal to the guarded machine. Light curtains: Light curtains have been assuring the safety of operators working at or near dangerous machinery for many years. The light curtain system works by creating an infra red detection plane across the danger area such that any intrusion into the plane results in a stop signal being sent to the machine and the danger being removed. Light curtains are an important tool in safeguarding hazardous machinery and have many advantages to the user in allowing excellent visibility of the working operation and speedy access to equipment which in turn promotes efficient working practice.
Light curtain specifications vary and should be chosen to suit the application to ensure adequate protection.
When using the Light Curtain or the Safety Mat it is important that they are spaced far enough away from the point of operation so that the motion can be stopped completely before the employee would be exposed to the hazard.
Today, many companies use the Job Safety Analysis/Job Hazard Analysis Process as an effective means of helping reduce incidents, accidents, and injuries in the workplace. It is an excellent tool to use during new employee orientations and training and can also be used to investigate &quot;near misses&quot; and accidents. Job safety analysis (JSA) is part of many existing accident prevention programs. In general, JSA breaks a job into basic steps, and identifies the hazards associated with each step. The JSA also prescribes controls for each hazard. A JSA is a chart listing these steps, hazards, and controls. There are many commercial vendors of Job Safety Analysis software. You also may want to consider performing a risk assessment such as ANSI B11.TR3-2000 Risk Assessment and Risk Reduction - A Guide to Estimate, Evaluate and Reduce Risks Associated with Machine Tools.
The control panel on the front of the injection molding machine features a Red Emergency Stop Button that stops all machine function when pressed. Emergency stop buttons may be placed at a variety of locations along the equipment to allow workers to immediately stop operation. In most cases, these are not to take the place of normal shutdown controls.
Signs are posted on a machine to inform us of hazardous areas. We are so used to looking at them that we often do not see them as we are running the molding machine. At the time of initial assignment and periodically afterward, it is good to review the different safety and warning signs on the injection molding machine and other equipment with employees to maintain an awareness or consciousness of the hazards that they identify.
A red sign indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. An orange sign indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury. A yellow sign indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury.
Place on each electrical cabinet and/or box containing dangerous high voltage.
Graphics can give examples of the part that is most likely to receive an injury from the hazard.
Effective warning signs have both graphical and written information.
Place on the purge guard. Graphics can give examples of the part that is most likely to receive an injury from the hazard.
A robot can be attached or placed adjacent to an injection molding machine to automate repetitive or potentially hazardous tasks. The robot must be guarded to prevent workers from entering or reaching into its space during operation.
Simple fixes are available to avoid injuries due to robots trapping a person. Place a fixed guard around the area where the robot operates. This type of guard could be an inconvenience when the robot and/or machine need to be worked on, but it is the most sure way to avoid trapping. A second method involves using safety mats around the area of operation. A safety mat is a device that disables the operation of the robot when sufficient weight (&lt; 10 pounds) is applied to the mat. . Thus, when a person walks up to the operational area of the robot, they step on the mat and the robot shuts down. Another method is to create a light curtain around the operational area of the robot. A light curtain operates in the same manner as the safety mats, except that it beams light around the operational area. Then, when one of the light beams are broken, the robot shuts down. All of these methods keep the person away from the robot during its motions.
Formed in 1957 to serve as the spokesperson for the U.S. plastics machinery industry, the SPI Machinery Division develops plastics machinery standards for promulgation through ANSI and the National Fire Protection Association Additional information can be found on the SPI Machinery Division&apos;s web site: http://www.plasticsmachinery.org/
Break the job into a sequence of steps. Each of the steps should accompany some major task. That task will consist of a series of movements. Look at each series of movement within that basic task. To complete a JSA effectively, you must identify the hazards or potential hazards associated with each step. Hazards contribute to accidents and injuries. All sources of energy must be identified. It is very important to look at the entire environment to determine every conceivable hazard that might exist. Using the Sequence of Basic Job Steps and Potential Hazards, decide what actions are necessary to eliminate, control, or minimize hazards that could lead to accidents, injuries, damage to the environment, or possible occupational illness. Each safe job procedure or action must correspond to the job steps and identified hazards. Everyone involved in implementing a job or task should be present when the JSA is written. The JSA should be reviewed, approved, and signed by the supervisor before the task is started. Understanding every job step is very important. Whenever a job step changes or a new step is introduced, the JSA must be reviewed and updated. Remember, the key reasons for completing a JSA are to encourage teamwork, to involve everyone performing the job in the process, and to elevate awareness.
Machine Guarding for Injection Molding Machines
OSHA 10-Hour Outreach Training Program for the
Plastics Processing Industry
A Presentation of the SPI-OSHA Alliance
• 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
• 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
Types of Injuries
• Cuts and bruises
• Sprains and strains
• 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
• 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
• 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
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
• Equipped with redundant
– Mechanical safety bar
• Allows the machine to
operate only when the
gate is closed
• Allows the electrical
system to operate and
close the clamp
• Actuated when the
operator’s gate is opened
• Prevents clamp from
closing when the
operator’s gate is open
Parts Discharge Guard
• Keeps employees
from reaching under
the operator’s gate
and into hazardous
• Covers the nozzle and
• In combination with PPE,
minimizes exposure to
molten plastic during purging
• Window allows observation
through purge guard, if
• Should be equipped with an
Injection Barrel Cover
• Protects from exposure
to high voltage and high
•Enclosure over moving
•Anti-kickback flaps in
•Proximity guarding –
distance from feed chute
to rotating knives
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
Abrasive Wheel Machinery
The distance between the wheel periphery and the
adjustable tongue must never exceed 1/4-inch.
flywheels, pulleys, belts,
chain drives, etc.) less
than 7 feet from the floor
or working platform must
Presence Sensing Devices
• Safety mat
• Light curtain
References for Injection Molding Safety
•ANSI/SPI B151.1- 1997 Horizontal Injection Molding
Machines - Safety Requirements for Manufacture, Care and
•ANSI B11.19-2003 Performance Criteria for Safeguarding
ANSI Standards are available at the following web site:
OSHA's Site-Specific Targeting (SST) Program
OSHA's Site-Specific Targeting (SST) program selects for inspection
individual worksites with the nation's highest Days Away from Work Injury
and Illness (DAFWII) Case Rate and Days Away, Restricted, or
Transferred (DART) Rates. It is based on data reported by more than
80,000 employers surveyed by the agency.
See the OSHA Web site for the
most current directive and the
rates used to target inspections.
In order to verify the reliability of
claims by establishments that
they have achieved low DART
rates, OSHA inspects a certain
percentage of employers with low
OSHA National Emphasis Program on Amputations
On October 27, 2006, the Occupational Safety and Health Administration (OSHA)
revised its national emphasis program aimed at reducing amputations in general
industry workplaces. The National Emphasis Program on Amputations targets
all types of machinery and equipment that are considered a high risk for causing
amputations. The plastics processing industry is among the industries under
scrutiny for workplace amputations.
The twenty-four states and two territories which operate their own OSHA programs
are encouraged, but not required, to adopt a similar emphasis program. State Plan
State information is available on OSHA’s Web site. The OSHA directive on this
emphasis program is available on OSHA's Web site under Regulations and
Compliance, subcategory Compliance Directives, No. CPL 03-00-003.
Under this initiative, regional and area OSHA offices will continue to conduct
outreach; targeting and selection; and inspections. 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
•Basic Job Steps
•Recommended Safe Job Procedures
• Injuries can occur while operating injection
• Risk areas can be protected by safety guards
• Protect yourself and operate injection molding
• Recognize the importance of a total safety
and health approach