A Slate Block Sawing Machine
Microcontroller Technology Enables Major Productivity Gains
Technologies used


Industrial sector (PRODCOM code)
    19 Leather Product Manufacture
    29 :Machinery
    361 Jewellery and Furniture
    20 Sawmilling and Planing of Wood

Alfred McAlpine Slate Limited is part of Alfred McAlpine plc which has a turnover of 1000 MEURO and 3200 employees. They operate several slate quarries in North Wales, with sales of 22 MEURO and 364 employees. One of these quarries is the Cwt-y-Bugail (Welsh for "the shepherd's hut") Quarry near Blaenau Ffestiniog, with sales of 3 MEURO and 60 employees. There has been quarrying at this site for some 150 years.

The company quarries slate, and processes this slate to produce roofing slate tiles, decorative floor tiles, and tile products for specific applications such as work surfaces, and ceremonial plaques (industry sector Prodcom code 1413 - quarrying of slate). The company's main market for its products is the building industry in the UK accounting for over 70% of sales.

The slate production process in common use throughout the industry is reliant on several traditional manual or manually controlled processes. The only significant process improvement achieved in the industry has been through the use of power tools.

One major process involved in the production of roofing slate is the sawing of the slate rocks into 300mm/450mm wide blocks for the subsequent slate splitting and dressing operations. This process involves the use of large circular saws fitted with diamond tipped blades to cut through the irregularly shaped rocks. The process is currently manually controlled, and this results in low process efficiency or frequent damage to the saw blade as the tip of the blade hits the slate rock at too high a speed.

The objective of this application experiment was to introduce a microcontroller based block sawing control system to improve the process efficiency and to increase the life of the diamond tipped blades.
The main functional features of the microcontroller based saw control system include:

  • Detecting the nearest point of the rock to the blade, so as to maximise the rate of advance of the saw towards the rock until the blade is about to reach the rock and thereafter to slow the advance speed to a minimum to prevent blade damage.
  • Controlling the rotational speed of the saw blade in relation to rock thickness automatically.
  • Detecting the point at which the rock has been sawn completely, so as return the saw to the start position again quickly and minimise the cycle time.
  • This process efficiency gain will increase company profits through reduced production costs, and assist in providing a more competitive position in the UK slate market.

The duration of the application experiment was 10 months. The development costs for the improved control system was 57 KEURO.

The company anticipates that the cost savings projected over the annual production volume will give a payback of less than 9 months for the application experiment costs of 57 KEURO. These cost efficiency savings will be obtained each year. However, it is reasonable to assume that the equipment will be replaced over a 10 year production period, and the return on investment on the initial application experiment funding will therefore, be 1,300%. The micro-electronic and management skills acquired during the experiment will be applicable elsewhere in the business.


    Alfred McAlpine Slate Limited
    Penrhyn Quarry
    Near Bangor
    LL57 4YG
    United Kingdom.

Detailed information

You can also benefit from microelectronics

Microcontroller technology provided Alfred McAlpine Slate Limited with the means of improving its products and enhancing its market position. You can also achieve significant benefits by acquiring the right microelectronics technology and utilising it in your product or manufacturing process. You can get help from FUSE to realise this.

FUSE is a technology transfer programme, funded by the European Commission to stimulate the wider use of microelectronics technologies by European enterprises to increase their competitiveness and enhance their economic growth. The demonstrator described here is one of many examples in the public FUSE portfolio covering the whole spectrum of microelectronics technologies and spanning a wide range of applications and industry sectors.

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