WHAT WENT WRONG
with some, the machine supplier may, in the interest of the cleaner, restrict access to certain areas of the control system. Machine computer controls are fairly straightforward, but it is important that you study the manual supplied with the machine and develop a good understanding of how it works and how to access the various fields relating to the program structures. Some computers may have set programs for, say, filter cleaning, that cannot be changed, but the cleaner can develop and save their own programmes if required, with cleaning processes structured to the cleaner’s
specific requirements. New machines normally come with correctly installed, suitably structured industry programmes, but over time these can be inadvertently or deliberately changed by staff or engineers, all of whom are unlikely to have the theoretical knowlege required to ensure that a programme is correctly constructed for a particular classification in terms of, for example, time, dip levels, temperature and mechanical action.
Make no mistake, computer programme errors, such as an incorrect temperature setting, can result serious fabric damage. To check an installed programme, refer
Examples of typical programmes for different classifications
1. Programme for normal robust items (labelled ) - Darks, Mediums and Lights 3 ½ min medium circulating dip from base tank. Drop to still – extract for ½ min.
8 min filter wash medium dip from distilled tank + detergent. Drop to base tank extract for 2 ½ min.
Dry at 60C for perc.CESS:
2. Programme for delicate Items (labelled ) - Darks, mediums and Lights. 2 min medium circulating dip from base tank. Drop to still – extract for ½ min. 5 min filter wash, medium dip from distilled tank + detergent. Drop to base tank - extract for 2 ½ min.
Dry at 50C for perc.
3. Programme for white items (labelled or ). The base tank solvent must be in good condition – no more that a very light straw colour with no cloudiness.
6 min filter wash, medium dip from base tank. Drop to still – extract for ½ min.
2 min medium circulating dip from distilled tank + detergent. Drop to base tank – extract for 2 ½ min.
Dry at 50C for perc.
When developing programme 3, it is critical that when the pre-coat circuit is employed in the first stage, the filter is producing crystal clear solvent before the cage inlet opens. Check in the relevant sight glass.
DELICATE PROCESS: For delicate items such as this silk dress develop a new programme in line with Programme 2 but use high dips and a 4 minute filter wash with intermittent cage rotation, if available
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to your machine manual for the computer instructions and access the programme you wish to review. You will find you can then step through the programme in detail stage by stage and check the following. The dip levels.
Slow speed cage rotation – rotation speed and whether continuous or intermittent The stage times The drain time Spin speed and time The drying temperature Bear in mind that not all machine computer controls have the capability to control features such as variable high- speed/low speed revs per minute (rpm) or to provide intermittent cage rotation.
Computer programming Those with an aptitude for IT will probably find inserting their own specific programs into the computer control unit fairly straightforward, but bear in mind that however confident you are in your ability, disaster can still be lying in wait just around the corner. In addition to a very careful review of the programme you have inserted (and adjusting it if necessary) it is imperative that you also monitor (in real time) the actual machine process delivered by your new programme. You should carefully check every aspect of the process structure. We have had direct experience with serious programming errors in new programs developed by acknowledged experts, because they had failed to monitor the process in real time after programming.
Examples of typical industry- standard hybrid programmes The following outline programme structures are suitable for perc and hydrocarbon solvents but, for optimum soil and stain removal, cleaning times (for which garments are tumbled in a dip or flow of solvent) may need to be extended. As a guide, for normally to heavily soiled items, cleaning time may need to be increased by as much as 15 – 20 minutes for robust items. Longer cleaning times are necessary because hydrocarbon has only one third of the solvent power of perc and weighs in at approximately 0.8 kg/ litre compared to perc at 1.6kg/litre. The low specific gravity of hydrocarbon means that mechanical action is substantially reduced, depending on machine capacity and for any given cleaning time.
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