Improving productivity

Measurement of UK productivity nationally has revealed a significant improvement since the turn of the century, which compares favourably with the considerable achievements in the second half of the last century. Productivity in the laundry sector varies widely it is probable that many laundries are outperforming the national average. We look at how the market leaders are becoming steadily more efficient and how individual laundies can emulate this.

Measuring productivity

Traditionally, laundry productivity in the UK has been measured in pieces per operator hour (ppoh), which provides a good indication of labour productivity. It relies on every hour spent on the laundry production line, in a hands-on role, being recorded, including a proportion of the time of working supervisors and even some managers on occasion. Comparison with other laundries is only meaningful where they are similar in work mix, with similar average piece weights. Measurement of increases in laundry ppoh has been found to correspond well with the annual increase in value added per operator hour, so it provides a fairy reliable benchmark for productivity in the laundering and textile rental sector. Many laundries are now moving to production measurement by weight rather than pieces.

Stimulating increases

Up until the 1950s, laundry productivity was thought to be driven by a combination of management effectiveness and financial inducements, in the form of bonuses for achieving specific output targets. However, over the next fifty years, improvements in machine design were found to dwarf financial incentives, with the advent of the tunnel washer and feeding/folding devices in particular revolutionising the volume potential of high-output laundries.

The 21st century has largely dispelled the myth that high-volume processing, with tunnel washers and tunnel finishers, necessarily meant compromising on quality,.With good management and well-trained laundry engineers a highly productive, high-volume laundry can produce products to meet market requirements.

The key feature which is the hallmark of the modern market leader in productivity terms is the thought which goes into making each individual laundry task easier and less time-consuming. This is seen as the significant step now required to raise the performance of a modern, well-equipped laundry from average to market leading. Where management has observed key steps carefully and devised correct handling equipment and methodology, improvements have followed rapidly. Where this has extended to working conditions (lighting, temperature, humidity and odour control) the improvements have sometimes been quite remarkable. But this does not mean that a well trained and experienced production manager is no longer required

Soiled linen collection

Traditionally, soiled linen was put into laundry bags by the customer, so that all the laundry van driver had to do was pick up the bag from the designated collection point – one bag, one trip on foot – and for small customers this is probably still the best method. As the scale of customers increase, many laundries have found that using a bespoke wheeled trollies are the most effective method. When the van is unloaded, the trolleys can be wheeled directly to the desired point in the laundry, with little or no lifting. Of course, this means matching the vehicle to the load, with tail-lift and so on. The important point to recognise is that you have now eliminated lifting and walking while carrying heavy, awkward loads, both at the customers’ premises and in the laundry. This immediately removes the strength requirement of the van driver, making the job accessible to a much wider proportion of the working population.

Some customers are prepared to pre-sort the soiled linen, saving time and reducing errors for the sorting team in the laundry. The annual price review time is often the best moment to negotiate this type of co-operation from the customer and it is surprising how often it is successful. It can even extend to a pocket search for workwear.

Sorting

It is surprising how sorting productivity varies from laundry to laundry. Even laundries with heavy investment in the latest high-volume washers sometimes fail to get this right. The key is to get the items loaded onto the sorting belt to arrive in front of the sorters correctly spaced, so that the sorter’s task is made easy. The worst arrangement is to have the work arriving in front of the sorters in little heaps that have to be separated out, before they can be directed to the right bag or bin. Even worse is to have a gap, with nothing on the belt for several seconds (or in some instances, several minutes!). You want the sorters to be working steadily and continuously, because this will dictate the minimum number of staff on the sorting belt and the easiest task for those employed.

It is not usually reasonable to expect the person loading the sorting belt to space every item out evenly. Best to arrange the conveyors from the unloading bay up to the sorting area to do this automatically.. You will need variable speed drives on all three conveyors, so that you can tune them to break up piles of work at each transfer point by operating at different speeds. You may find you need large differences, with the initial conveyor from the unloading bay running the slowest, and the receiving conveyors running progressively faster.

Washing

Modern high-volume tunnel washers will only deliver their design output if they are loaded to their design capacity, with the classifications correctly sequenced. This requires several key checks:

1. You need to check the calibration of the weigh scales regularly (at least monthly and more frequently if you find discrepancies), so that you can load confidently to the correct load weight.
2. The correct load weight for used towels is usually above the design load weight for dry sheets and pillowcases, to allow for average moisture content (towels get wet in use). Check you are getting this right by weighing a few batches of towels from the dryers regularly (say three or four batches per week). This alone could raise towel productivity by up to 20% if you have been loading to the same weight as dry work.
3. Space the full dry work batches in the washer (towelling and robes) so that multiple batches do not block the dryers and cause a ‘tumbler hold’, when the dryers cannot accept the next load when it is ready to discharge from the press, because a long drying cycle. This will depend on how many dryers you have and how quickly they fully dry a batch.
4. Programme dryers so the cheeses to be ironed dry are only tumbled for 30 seconds or so (just enough to break up the cheese). This will free up valuable tumbler minutes, help to avoid tumbler holds and save considerable energy (thermal efficiency of the dryers is only half that of ironers).

Drying

Even with the greatest care with load weights and timer settings, it is difficult to get drying times correct, to eliminate towel greying in the dryer and to minimise energy consumption. Usually, by far the best solution is to fit automatic cycle terminators to those dryers which might handle full dry work. These need to be set up carefully – get help with this if you need it, because it is important. They then need to be cleaned regularly, with frequent checks on the final moisture content.

Ironing

High productivity and good energy efficiency demand minimising conditioning in the dryers of work to be ironed. If this poses any problem at the ironers, then check the following: 

1. Check the moisture content of the textiles as they leave the de-watering press or on removal from the washer extractor. This should be below 50% for cotton sheets or below 54% for cotton towels. Your design press pressure should be being maintained for at least 30 seconds. Your final spin time in the washer extractor should be such that spinning for another 30 seconds does not remove any more moisture.
2. Use an infra-red thermometer to check for cold spots on the beds. Cold spots on a steam heated unit can often be cured by checking for and eliminating any wetness in the steam caused by poor pipe insulation or carryover from the boiler. Once these are all right, then check for defective steam traps. Use traps which discharge condensate as it is being formed, such as float or inverted bucket designs.
3. Carefully use a piece of calender tape to heck the fit of the cylindrical roll into the curved bed. Lower a short piece into the in-running nip to each roll in turn; you should feel the nip start to grab the tape after it has gone in by 15 – 20cm. Then let it go. If the roll is undersized , re-clothe it in line with the manufacturer’s instructions.
4. Check the vacuum across each roll with a surface vacuum gauge. You need vacuum, with the strongest vacuum to the front roll. If the clothing is blinded, check your waxing method and your starching contamination. Be prepared to clean out any wax deposits on the vacuum pump blades or in the ductwork. Check for leaks at joints, including the rotary joint at the roll end.

Conclusion

The difference between the highest and lowest productivity varies between 60 and 200 ppoh, with tunnel washer-based flatwork plants now achieving figures towards 200 ppoh on a regular basis. However, there is massive scope in most plants to make significant improvements, given the time and effort and required. This month’s tips are only a brief introduction to what is needed and we shall return to this topic again in the future.

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