In steps 1 – 3 the main objective was to eliminate FORCED DETERIORATION:
Now it’s time to talk about:
Autonomous Maintenance Step 4 “General Inspections”
Definition Of Step 4 General Inspection
Consists of upgrading the operators knowledge and skills related to the machine sub systems, with the intention of eliminating breakdowns due to natural deterioration.
In this step certain activities are developed such as sub system classification and training, putting and solving f-tags ,transferring the knowledge from EM to AM and finally reviewing the CIL standards.
Objective of Step 4
- To improve the knowledge of the operator in understanding the functions and components of the equipment.
- To execute detailed inspections , based on the ability to find abnormalities
- Execute the small repairs.
- How do we do this ??
Updating Inspection Standards
- Using the funnel method we can determine which tasks can be safely transferred to AM from EM(PM)
ex. Inspection and Lubrication, funnelled down AM.
Definitions of the Modules
Prioritizing the Training Modules
- Fasteners – nuts, bolts, screws, tools….
- Transmission – chains, sprockets, moving parts…
- Pneumatics – cylinders, air lines, solenoid valves…
- Electrical/Instrumentation – sensors…
Applying the Training
Training begins with the most important module……System of fasteners 4.1
- To be able to do inspections and maintain the basic condition of the equipment.
- To ensure that employees use proper inspection procedures. (to maintain basic equipment conditions).
- To introduce improvements to the equipment so that it allows for easier inspections (Checklist) and perfect visual controls.
TO RAISE OUR LEVEL OF KNOWLEDGE AND ABILITIES!
Specific characteristics of screws;
Types of fasteners;
Different heads used on fasteners;
Types of threads;
Types of nuts;
Types and functions washers;
Assembling nuts, screws and washers;
Use of tools;
Visual control of fasteners.
Objectives of this Training
To give the operator the knowledge and basic abilities to Inspect and Correct situations involving fasteners.
- At the end of this training operators will be capable of:
- Identifying defects in fasteners
- Able to correct defects in fasteners;
- Able to maintain the fasteners to established standards;
- Have the knowledge to improve the application of fasteners;
Eliminate accidents to operators from the incorrect use of tools:
To ensure the correct tools are used:
Prevent damage to the tools:
Prevent Damage to the equipment;
Prevent Damage to Nuts and Screws;
Have the ability to work with assurance and confidence when using tools:
Reminder: The damage to fasteners is not caused by adjusting them, it is caused by how the tools are being used to adjust the fasteners.
How to take care of your tools
- After using your tools you need to keep them clean.
- Only use the tools for the task they were designed for.
- Store tools in their designated location.
Application of the Manual Tools
They are a lot of manual tools designed to tighten and loosen the various types of bolts and screws used on our equipment.
The types of tools that are commonly used in production plant are:
1 – Wrenches (Open and Closed)
2 – Screw drivers – (Philips – Straight – Robertson)
3 – Allen wrenches
4 – Hammers
Adjustable Wrenches? Are BAD TOOLS for many reasons.
Application: This tool is used to tighten or loosen nuts and bolts with a square or hexagonal profile. They can be found in both SAE (inches) or metric (millimeters).
TYPES OF FIXED END WRENCHES
Fixed-end wrenches come in three basic styles, open, boxed and combination. Wrench sizes are either measured in SAE (inches) or metric (millimeters) and come in many shapes and configuration. All serve the same basic function, loosening or tightening nuts and bolts. The boxed end of the wrench allows for more surface area to be covered on the bolt or nut.
Above is an example of a combination wrench. A combination wrench has an open end on one end and a boxed end on the other.
Here an open end and boxed end wrench is being used to tighten a bolt. Notice the wrench on the back side holding the nut while the bolt is being turned by either the open or boxed end wrench.
A combination wrench is nothing more than open end and box end wrench on the same handle. Where the open wrench will have an open end on both end of the same handle, usually of different sizes or offsets. The same also applies to the box end wrench.
Application: Its application is mainly used for nuts and bolts with hexagon heads. It is extremely practical, it has an open mouth on one end and the other side is a closed. This design facilitates the work when the closed end can not be used because of a hard to access area.
How to care for Wrenches
- Never use it as a Pry Bar
- Always think of a clock: clock wise is tightening – counter clockwise is loosening – for example: a bottle of water twisting the cap clockwise tightens it; counterclockwise loosens it) Ensure that the opening of the wrench is fitted properly on the head of the nut or bolt
- Do not use a hammer to hit the Wrench to loosen nuts or bolts
There are many sizes and shapes of screw drivers. They are connected with a rod to a handle (certain types of screw drivers can be used in electrical situations). Most screwdrivers have a tip that is tempered, this prevents it from twisting . There are also special right angle screw drivers that allow for access to hard to reach areas.
The screwdriver is a hand tool that is used for turning screws. The screwdriver has three main parts: the blade, shank, and handle.
The blade, or commonly known as the tip, is the end of the screwdriver that fits into the head of a screw. Screwdriver blades are manufactured in several different styles. Each style screw has its own purpose in either manufacturing, aesthetic appeal, uniformity or preference. Though the style of the blade may change the function of a screwdriver is still the same, to increase the torque that is applied to the head of a screw. The part that connects the blade and the handle is the shank. The handle is molded to the shank. Screwdriver handles are made from various materials, including wood, plastic, and rubber. The blade and shank are always made of metal.
TYPES OF SCREWDRIVERS
The flat-bladed screwdriver is the most frequently used type of screwdriver. Another popular type of screwdriver is the Robertson (square) screwdriver.
Flat Blade Screwdriver
When choosing a flat blade screwdriver it’s very important to size the blade or tip to match closely with the slot of the screw. A blade that is too small exerts forces only on the outer 2 edges of the blade. This can cause the screwdriver blade to twist or break. In addition to damaging the screwdriver damage to the head of the screw may also be generated. Finally, the risk of an injury increases due to the fact it takes more downward force to hold the screwdriver in the slot of the head which increases the chance of slipping.
blade that is too large also has it’s disadvantages. It can also cause blade slippage and rounding off of the screw or bolt. When the blade doesn’t reach the bottom of the screw head all the pressure for torquing the screw is exerted on the very top portion of the head. Acting as a wedge this can pry the screw head open, either breaking it or rounding it off.
Flat Blade Screwdriver
When choosing a flat blade screwdriver make sure you pick the one that has the most surface contact in the head of the screw.
Use a good downward pressure because screwdriver blades are tapered this acts as a ramp wanting to lift the blade out of the screw slot.
A good fit will distribute equal pressure across the blade.
ROBERTSON – SCREWDRIVER (SQUARE)
The Robertson screw driver was invented by a Canadian in 1908 by P.L. Robertson, a native Canadian. The widely used screwdriver is the Robertson (square) screwdriver which has a square shaped head. The Robertson screwdriver functions and operates in much of the same manner as the flat blade screwdriver. One advantage of using a Robertson head screwdriver is that there is less chance of it slipping off the screw head unlike the flat blade. For this reason, Robertson head screws are commonly used you can find them in deck screws and on construction sites in home building. The square surfaces fit nicely into the square shape on the top of screws that enable the square-shaped screwdriver to make secure contact with the screw. As the screwdriver is rotated, it is far less likely to slip out of place and the process moves a lot faster.
Care must be taken when using any screwdriver. Do not hold work pieces in ways that would expose the risk of an injury. Injury to the hand can result should the screwdriver slip.
Do not use a screwdriver as a wedge or lever. The blade tip can break off and cause an injury or damage the tool.
Do not hit a screwdriver with a hammer, unless it’s a specially designed one.
The blows from the hammer can split the handle, bend the shank, or damage the blade.
RULES FOR SAFE AND EFFECTIVE USE OF SCREWDRIVERS
Six basic rules to follow for the safe and effective use of screwdrivers are:
- Always select the proper blade and blade tip size of the screw head.
- The blade tip of screwdriver should be kept flat, square, and free of burrs and chips.
- Keep the handles of screwdrivers free of oil and grease.
- Do not use a screwdriver as a punch or chisel.
- Never use a screwdriver in conjunction with pliers or a wrench to attempt to increase torque.
- Always keep the blade of a screwdriver pointed away from people. Never hold a piece of work by hand when driving a screw.
ALLEN KEYS (WRENCHES)
Hexagonal key (Allen) Allen keys are found in two versions: Normal and Long.
An Allen wrench is commonly used to remove and install an Allen-head bolt. The Allen-head bolt has the advantage of requiring smaller diameter counter-bores for deeply set fasteners, and the Allen-head bolt has very narrow flanges.
PLASTIC HAMMER (MALLET)
Plastic hammers are for hammering small items that you do not want to damage. This type of hammer has a sacrificial heads, meaning the head will break before the damaging what you are hitting. Typical use is tapping a small bearing into a housing.
Note: Never use a hammer that has a damaged face. A damaged hammer must be replaced
RULES FOR SAFE AND EFFECTIVE USE OF HAMMERS
There are three basic rules for the safe and effective use of hammers.
- Keep the handle and face of the hammer free of oil and grease.
- Replace the hammer if the face of the hammer is damaged.
- Never leave a hammer overhead. The hammer could fall and cause an injury
Hand Tool Summary
From this Module you should remember the following points for Step 4.1 training:
Screwdriver is a hand tool that is used for turning screws. The two most commonly used screwdrivers are: Flat-head and Robertson (square head)
Flat-head screwdrivers are used on a single slotted screw. The flat portion of the blade should fit into a slot on the screw head. It is very important to size the blade or tip to match closely with the slot screw.
Robertson – (square) head screw drivers fit a Robertson square screw.
Never use a screwdriver that is broken or bent. Never use a screwdriver as a wedge or lever. Do not hit screwdrivers with a hammer. Do not hold parts or pieces of work in your hand while using the screwdriver, your hand could slip and you could stab yourself with the screwdriver.
NUTS AND BOLTS
Nuts / Bolts / Screws
Bolts and screws are two terms that commonly interchange with one another. In many cases when working with metal machinery the term bolt will be used. In working with wood or lightweight sheet metal the term screw is commonly used. For the most part bolts and screws function in the same manner.
Bolt – A threaded fastener intended to be mated with a nut. Commonly used to join two or more pieces of material together.
Screw – A rod shaped piece with a spiral groove and a slotted or recessed head design to be inserted into material by rotating used for fastening pieces together.
Basic Components, Bolts / Screws
Note: In many cases washers are used in conjunction with nut and bolts. This will be cover in more detail later in this book.
Basic Components, Standard / Metric
Up to this point you’ve learned some very basics on nuts and bolts. Though there are hundreds of other types of nuts and bolts in the world we tried to focus on what’s most commonly used in the plant. Notice the basic components are almost always the same, variation will be found in the head style and type, diameters either metric or standard and thread count per inch or millimeter.
Nuts are threaded components used to mate with a bolt type fasteners, producing tension on the bolt and compression on the bolted materials. The material and grade of a nut should be of equal material and grade as the bolt. Though nuts come in many styles, the hex nut is the most commonly used nut in the plant. Two main types of hex nuts are the Free Spinning and Locking nut.
A free spinning nuts turn freely until it sits against its base. Further tightening of the nut forces the threads to act as a wedge and lock the nut in place.
Locking nuts are designed to hold a bolt in place when vibration is a factor.
There are several style of locking nuts. The most commonly used locking nuts are the Nylon Insert and the Distorted Thread nut.
Nylon Locking Nut:
The Nylon Locking nut uses a Nylon Insert on the top portion of the nut to grip the threads. The inserts are not threaded so when the bolt comes through, the nylon conforms to the thread gripping them. The nylon expands and forms a tight fit around the thread, locking the nut in place.
There are several types of washers the most common are the flat and lock washers.
Flat washers have 3 primary function.
- Is to reduce the chance of a nut backing off when fasteners are used on vibrating equipment. The washer acts as a bearing between the nut and the surface of the bolted material.
- Flat washers distribute their friction force area over a wider area.
- Flat washers help spread the load over oversized holes or slots when otherwise a nut or bolt head may pull through the hole.
Lock washers serve one purpose, to keep nuts from vibrating off. The sharp point on a lock washer digs into the surfaces of the nut and bolted material creating a burr. These burrs increase the friction between the three materials and reduce the chance of the nut backing off.
Cotter Pins are fasteners inserted into a hole preventing nuts, shafts or chains from coming loose. For example the ladder for line 21 has a cotter pin to lock in place the handle.
This pressure clamp is ideal for maintenance applications on rubber or hoses. It is a system of securing hoses or two pieces of materials together, that prevent it from coming apart under pressure.
In the assembly, of the clamp it is important to verify that the clamp is secured, if at the nut does not tighten and continues to spin freely then the clamp is no longer working properly and needs to be changed.
From this Module you should remember the following points for Step 4.1 Fastener training:
- Identify different types of fasteners.
- Identify the components of a fastener.
- Know and understand when to use fasteners.
- Identify the types of fasteners used at production facility:
Identify the components of a fastener:
Bolt /Screw – Basic components are almost always the same, variation will be found in the head style and type. There are standard and metric bolts. Thread size on a bolt/screw also varies. When deciding what size bolt you need, take the bolt and match the head and thread types with a new bolt.
Nuts – All nuts are basically the same. The nuts are threaded components used to mate with a bolt.
Washers – A flat circular piece of metal which corresponds to a bolt size.
Know and understand when to use fasteners:
A Bolt is a thread fastener intended to mate with a nut. Commonly used to join two or more pieces of material together.
A Screw is a male shape or rod shaped piece with a spiral grove and a slotted or recessed head designed to be inserted into material by rotating and used for fastening pieces of solid material together.
A Nut is a metal piece with an internal screw thread and is used on a bolt or screw for tightening or holding something together.
A Cotter Pin is a half-rounded metal strip bent into a pin whose ends can be flared after insertion through a slot or hole. Cotter Pins are commonly used to hold together chains.
A Washer is a flat thin ring used in joints or assemblies to ensure tightness, or prevent leakage.
Identifying Critical Fasteners