FAQs - Four-sided Planing and Moulding Machines
Should Four-sided Planer Moulders be braked?
Four-sided planer moulders fall within the group of woodworking machines that require employers to carry out a risk assessment to find out if they need to fit brakes. However, Woodworking Information Sheet No. 38 PUWER 98: Retrofitting of braking to woodworking machines advises that the only reason for not fitting brakes would be if there was no added benefit. An example of this would be if the machine was in an enclosure with interlocked doors, where the interlocks prevented the doors being opened until the cutters had come to rest, using either a time delay or a stop/motion sensor.
Woodworking Information Sheet No.40 Safe use of four sided moulding machines provides good reasons for braking to be fitted:
- On older four-sided planer moulders the spindle stopping time can be as high as five minutes.
- Most accidents could have been prevented if the cutters had come to rest before operators approached them.
- Out of 125 accidents investigated access to the cutters with the machinery running was only necessary in 17 cases.
- About half of all accidents were caused by people approaching the cutters.
In summary, four-sided planer moulders should normally be braked as they will then be safer and can be stopped and reset quickly so there will be less time lost. In addition, if a tool breaks, stopping the machine quickly will reduce the amount of damage that takes place.
On new machines interlocks are fitted to enclosure access doors that cut power, stop the feed and apply brakes. What is the standard for older machines?
On older machines fitted with a "wooden box" type enclosure simple locks and bolts will not prevent access to the enclosure with the machine running unless braking has been fitted and employees are trained and instructed to operate the brake and stop the machine before entering.
As a standard, machines should have an enclosure and braking should be fitted. In some cases interlocks on doors linked to the braking may also be beneficial. However, this will be dependant on the machines characteristics and system of work that must be employed with it, particularly for setting (see Q.3).
Considering the high number of accidents that occur during adjusting and setting four sided-planer moulders, how should setting be done safely, particularly on an old machine?
During setting it is a requirement for the heads to be running as the trial piece of material is 'inched through' the machine and the cutters are correctly adjusted.
Old machines may not have the remote setting /adjusting mode of newer machines and in some cases cutter adjustment must take place locally. Where an enclosure has been fitted the setter therefore has to work inside it. In these circumstances, if interlocks were fitted to the doors they would have to be closed to allow the machine to run. The setter would therefore be required to work alone inside the sealed enclosure and this could increase the safety risk. In addition, there will also be a higher exposure to noise and dust. This is why careful consideration is needed before fitting interlocks on the enclosure doors. Other options, such as a lock with controlled key access, may be more appropriate.
During setting operations it is very important that all cutters have been effectively guarded and this is normally achieved in two ways:
- Hood/extraction enclosures around the cutter blocks, particularly the vertical and horizontal top cutter blocks, which also provides effective guarding.
- A bridge type guard, similar to that used on a hand fed surface planer that covers the bottom horizontal heads.
- Guards are only removed or opened when the machine is stopped and being cleaned/maintained or a cutter block is being fitted to the spindle during a tool changing operation.
The normal expectation is that guards are fitted and closed during setting. However, on some of the older machines setters have reported that they need to be able to actually see the cutters during final adjustment and have been known to have the hood guards in the open position during setting. If this practice is identified during the risk assessment and confirmed to be an actual requirement then additional mesh guards must be fitted between the hood guard and the cutters. They should be designed to allow observation of the cutters during setting but be able to prevent any risk of contact with the cutters. They must also only be able to be opened or removed by a specialist tool. Care must be taken that the mesh guards are not detrimental to the extraction system and if so, they should only be fitted and used for setting and removed prior to normal machine operation.
Because of the dangers associated with setting it is essential that a machine specific risk assessment that considers safety and health issues has been completed. This should then be used to produce a safe system of work for the setting operation. The following topics should be considered:
- Only adequately trained and experienced employees should be authorised to carry out setting and adjustment and only the setter should be allowed in the working area of the machine during setting operations.
- Access to cutters must be prevented during setting.
- Suitable eye, ear and foot protection must be worn and RPE (Respiratory protective equipment) if necessary. There should be no loose clothing that could cause entanglement.
- The correct tools and equipment must be used and be located in a safe area.
- The immediate floor area must be clean and kept clear of all obstructions and tripping hazards.
- Fitting cutters
- Many injuries occur when cutter blocks are being handled, either because of the sharp cutters or the weight of the block.
- Protective gloves should be worn, suitable for handling sharp and possibly oily cutter blocks. Gloves should provide a good grip and be able to prevent cuts and abrasions.
- Cutter blocks can weigh up to 30 kg and may need to be fitted at arms length so the risk of injuries can be high. Cutters should therefore be moved on a trolley and a mechanical device to help them being lifted on and off the spindle may be needed.