Select the right tool for the right application -
What is the required torque?
What is the joint condition?
Are you using the correct sockets? Use of high quality Impact sockets of the correct length and fitment ensure effective transfer of torque.
What is the working air pressure at the inlet of the tool?
The tools are designed at rated performance at working air pressure of 6 Kg/cm². However a minimum of 5 Kg/cm². air pressure is required at all times.
What is the cycle time of fastening?
A good cycle time is considered when the tool runs on the joint between 3-5 seconds. Application where the tool runs more than the above window calls for review of tool selection or preventive maintenance etc.
Are you using the correct diameter of hoses?
Ensure the tool is connected to the specified hose diameter or else the tools will be running at lower ratings.
Look after the wrenches well. Attend preventive check on the impact section by greasing every 50,000 cycles or so. If the assembly line is heavy duty then the frequency can be increased. Add a few drops of light spindle oil in the inlet of the tool before start of the shift. Check the FRL unit or the central lubrication unit has the specified grade of oil and the tool is fed oil droplets at regular intervals during the course of its use.
No moisture please.
Moisture is the main cause for premature failure of the pneumatic tools. The damage the motor parts as well as run the tools in lower ratings without the knowledge of the operator.
Use and follow best practices.
Look after the tools well. Proper handling and usage will give durable trouble free performance. Check balancer settings for ease of handling. If the tools are on ground level ensure they are stored in a holder with protective rubber lining. Check you air line for air leakages. Air leakages mean loss of energy and waste. Use good quality QRC and end fittings. Use the tools with protective gear such as hand gloves / ear plugs.
Selection of Pneumatic Tools
For Selection of the tool, we should know: --
1. Application – Screw, Bolt OR Nut & their sizes.
2. What is the grade of fastener?
3. How much is the target torque? & accuracy?
4. The joint condition – hard / soft
5. How much is run down / free running?
6. Is there any prevailing Torque?
7. Material of component – Metal, Rubber or Plastic
Impact wrenches are not designed for torque control. So their operator is likely to use them to tighten each nut to its maximum torque or until the wrench is unable to turn the nut. Pulse wrenches, in contrast, are pre-set tools & use their oil cylinders to slip when the desired, pre-set amount of torque is reached. As a result, nuts and bolts tightened by pulse tools will be torqued to the amount specified by your design team. Especially for pulse tools the joint should be hard joint (metal to metal contact). Fastener i.e. nuts & bolts should be as per standard.
The socket for pulse tools the socket should be of standard length
The duty cycle (Number of tightening per tool per day) of pulse tool should not be extra ordinary.
A good cycle time is - 3 to 5 sec.
Fewer the vanes , higher the Speed.
Higher the vanes, higher the Torque.
Greater the speed – Less stall torque & High CFM.
Lesser the speed – Greater stall torque & less CFM.
Pneumatic tools are powered by the flow and pressure of a compressed air. Pneumatic tools have a higher power-to-weight ratio than electric power tools. Applications for pneumatic tools include assembly (with nuts, bolts, screws), hammering, bulk material removal, surface finishing, hole drilling, metal cutting, fine material removal, etc. Specialty pneumatic tools are also available. Air operated drives are extremely robust. The internal overpressure prevents the penetration of dust or dirt. Only the low cost vanes need to be exchanged as wear parts. Necessary repairs are simple and can be done easily and safely by a trained maintenance person. No electricity specialist is necessary. Hence lowers TOC - Total Ownership Cost.
Types of Pneumatic Tools
There are many different types of pneumatic tools which include –
Pneumatic transducerised oil pulse tools with controllers,
Shut-off & non shut-off type pneumatic oil pulse tools,
Air impact wrenches,
Air screw drivers (shut-off type, with slip clutch & impact type),
Air ratchet wrenches,
Pneumatic drill machines, grinders & sanders etc.
Working of Pneumatic Tools
An air impact wrench stores energy in a rotating mass or hammer for delivery to an output shaft. Oil pulse tools have always been known for their ergonomic benefits and high run-down speeds. In oil pulse tools hammer mechanism is replaced by oil pulse unit. Hence no "metal to metal" contact which provides softer and stable "impulsing“ resulting in less vibration, lower noise levels and longer service life when compared with conventional impact wrenches. Auto shut-off oil pulse tool is preferred if the aim is to reduce operator influence. With appropriate setting of torque within the range of the tool, the tool will shut off on achieving the pre-set torque by cutting off the air supply to the motor. The result is increased accuracy and faster tightening. Pneumatic transducerised oil pulse tools with controllers provide torque feedback and controlled shut-off of the tool in closed loop. Provides traceability because of torque validation (Date & Time stamped). This effective Poka-yoke solution gives complete control on fastening process. Pneumatic screwdrivers are automated tools that turn screws while providing close control of screw torque.
Pneumatic grinders / sanders use an abrasive bonded to a wheel, belt, or disc to remove material and improve surface finish.