Maintenance Tables

Safety During Maintenance

Safety precautions for maintenance work

Qualified personnel	Maintenance work may be carried out only by personnel with the appropriate specialist training.
Observation of General Machine Documentation	The maintenance activities and intervals regarding replacement of consumables and wear parts, as specified in the General Machine Documentation, must be adhered to.
Appointment of supervisory personnel	The operating personnel must be notified prior to commencement of any maintenance work. A head supervisor is to be appointed.
First steps	The following safety precautions must be taken before carrying out any maintenance work: Position the machine parts in such a way that the part to be serviced is easily accessible. Before removing any guard panels, make sure that the machine is in the appropriate operating status and secure it against being switched on. Provide support for vertical slides or similar machine parts prior to all work in their area. If necessary, demarcate the maintenance area as appropriate and place warning signs.
Exercise caution when carrying out maintenance work	In the following cases, no persons must be in the machine's danger area. If machine movements can be carried out. If any pressure lines or vessels are under pressure. If any electrical components are live.
Transport of sub-assemblies	When replacing larger sub-assemblies, these must be carefully attached and secured to lifting gear.
	See also: "Safety during transport work"
Use of working aids	For assembly work above floor level, use appropriate steps and working platforms that comply to applicable safety standards. Do not use machine parts as steps or working platforms. For maintenance work at greater heights, safety harnesses must be worn. Keep all handles, treads, railings, platforms, and ladders free from dirt and lubricants.
Use of appropriate tools	Appropriate workshop equipment is essential for carrying out maintenance work.
Involved parties shall communicate with each other	Working in teams, the involved persons must be able to make themselves understood to their work colleagues, even if a high noise level or other environmental influences make communication difficult. Commands and feedback must be defined before each working step to ensure an efficient coordination.
Completion of work	After work at vertical slides or similar machine parts, provided supports must be removed. If, in the course of maintenance work, guard panels and safety devices were removed, these must be refitted immediately after completion of the work and their functionality tested. Loosened screw connections must be re-tightened to the correct torque and screw retainers put back in place.

Cleaning the machine

Detergents

The machine must not be cleaned using substances that cause irritation or are harmful to health or the environment, such as chlorinated hydrocarbons (PER, TRI etc.).

Ensure that cleaning agents are disposed of in an environment friendly way.

Do not use cleaning devices

Under no circumstances should steam or water jets or compressed air be used for cleaning, as there is a risk of dirt or cleaning agents getting into the guideways or seals. This can impair the function of switching elements or measuring systems.

Removing swarf

Remove chips using an appropriate tool such as a hand broom. Do not touch swarf with bare hands: wear suitable protective gloves.

Safety when working on hydraulic, pneumatic, lubrication or lubricating coolant supply systems

Applicable regulations and skilled personnel	Work on hydraulic, pneumatic, lubrication or cooling lubricant systems is to be carried out only by suitably trained persons; applicable regulations and codes of practice must be adhered to.
Releasing pressure	Before disconnecting any line or removing a control or drive unit, the system must be relieved from pressure. Procedure: Lower or support any loads. Switch off pump. Release pressure from vessel. Even on machines equipped with an automatic pressure release facility, the pressure gauges should be checked to ensure that there is no residual pressure in the system.
Regular inspection of fittings	The integrity of pressure lines and connectors must be checked at regular intervals and replaced even if only slight damage is apparent. Fluids escaping under high pressure pose a risk of injury, explosion and fire. Any leaks and damages to hoses and pressure lines must therefore be rectified immediately. Escape of oil into the ground must be prevented under all circumstances.
Pressure hoses	Pressure hoses must be replaced regularly according to applicable regulations.
Professional connection	Hydraulic and compressed air lines must be routed and connected correctly. It must be ensured that connectors are not mixed up. All fittings, as well as the length and quality of the hose lines must comply with technical requirements.
Correct venting of lines	If, during re-commissioning after repairs or moving of the machine, any air remaining in the hydraulic system is not purged, damage to tubing, hosing and machine components may result.

Safety when working on electrical equipment

Applicable regulations and skilled personnel	Work on electrical equipment and in the control cabinet should be carried out only by qualified engineers. The guidelines and regulations for setting up and operating electrical equipment applicable to the installation site must be respected.
Isolating the machine	Machine and installation components on which maintenance work is to be carried out must - if specified - be isolated from the electrical power supply. First ensure that the isolated components are voltage free and then earth and short-circuit them and isolate them from adjacent, live modules. Note that the control cabinet is still live when the main switch has been turned off.
Interference voltage circuits	If interference voltage circuits are present, these must be isolated separately. Note that the control cabinet is still live when the main switch has been turned off.
Stored electrical charges	Watch out for residual or stored electric charges. Use a measuring device to check that components are not live.
Working on high-voltage assemblies	Before working on high voltage assemblies, connect the mains cable to earth after isolating the power supply. Capacitors must be short circuited with an earth rod.
Guarding the danger area	The danger area must be guarded and identified with a warning sign.
Original fuses	Use only original fuses with the specified current strength and the specified time response behaviour.
Handling of faults	If a fault occurs in the power supply system, switch off the machine immediately.
Earthed tools	When working with earthed tools, such as soldering irons and electric hand drills, the machine main switch and, if applicable, any external power circuits must be switched off.
Printed circuit boards and connectors	Isolate the machine from the power supply before removing printed circuit boards or connectors. Protect unused connectors from dirt by using blanking covers and plugs.

Safety during troubleshoot and fault rectification

Act with special caution in the event of fault

If a fault occurs on the machine, special caution must be exercised. The fault as well as improper interventions by staff can cause consecutive errors. Especially in the event of error burst, the machine's reaction is unpredictable.

Initial precautions

Urgent measures to be taken:

Immediately interrupt active automatic programs.
Switch off motors.
If required, press EMERGENCY STOP, or switch off the machine's main switch and secure against switching on again.

Inform responsible persons:

Strict compliance with scheduled workflow is required.
Immediately inform the person having a key to enable special operating modes. Special operating modes that allow fast axis and spindle movements with the work area safety door open must not be enabled on faulty machines.

Working inside the operating machine

If entering the machine in ON state during troubleshooting or fault rectification is unavoidable, all applicable measures to avoid

Clarify what movable parts are present in the work area and what function and travel range these parts do have. Ensure that there is always a safe escape route from the hazard area. Block any hazardous, movable machine parts using timber beams.
Ascertain whether the machine or individual parts possibly can start up automatically. Typical cases:

Times at which the warmup program starts
Times at which the washing programme of a rack-type magazine starts
Machine parts with inherent power supply and/or control (pallet magazine, automatic loading system, linked machines, cooling lubricant unit, chip conveyor)

Ascertain whether there are further risks, for example due to pressurised media or electric tensions.
Call in a second person, who activates the EMERGENCY STOP device or turns the main switch off in an emergency. Ensure that involved persons are able to make themselves understood to each other.
Keep unauthorised persons away from the machine. Cordon off access to the machine and attach warning signs.
Ensure that motors are switched off.
In order to prevent unauthorised persons from triggering fast axis movements accidentally, open the work area safety door and secure it against being closed by means of a hook padlock. But note that, under certain conditions, axis movements at reduced speed can still be triggered even with the work area safety door open.
Leave the danger zone before machine movements are activated.