Sunday, 14 February 2010

The Bowls Manufacturing Process

Step 1. Black Bowls are made from a Phenol Formaldehyde grey powder, with a dye added to make them black. Some coloured bowls are made from Melamine, which starts life as crystals, the crystal being the colour of the bowl, so the colour is right through the bowl, this is extremely strong, and offer very good non-fade characteristics. Others are made by adding a dye to their powder.

Step 2. The raw materials are then weighed very carefully for the various models and sizes. using a high frequency pre heater, the granules are then melted down to form a putty like substance, which is then poured into a mould, which resembles the shape of the bowl. Different moulds are used for various models.

Step 3. A 150 ton press then compresses the material, which squeeze out excess gases & liquids from the mould. Some of this excess remains around the bowl, which is then trimmed off with a hot knife later in the process, this is the ring that can sometimes be seen around the running surface of the bowl. Bowls are moulded in one piece, lugs still remain on the bowl for the next part of tooling process, however the moulding must first cure, and this can take up to 10 days. Once cured the bowl is ultrasonically tested to check for air bubbles (trapped gases) which if found means the bowl is completely discarded as waste.

Step 4. After this important process the bowls goes to the diamond bit lathe, once mounted a specific computer programme for the bias of this particular bowl is punched in, and the bias of this particular bowl is cut to shape in seconds with extreme precision.

Step 5. Now the bowls will ave either dimple or rings cut in. A cutting/drilling machine holds the bowl by suction, so the rings or dimples can be cut or drilled in with the utmost accuracy. The bowl is now begining to resembe a bowl, but is un polished. An experienced highly trained person now matches 4 bowls for weight, there is a tolerance of only 3gms between the 4 bowls permitted, the bowls are then marked with a code, and travel around the factory as a set.

Step 6. At this point the first table test occures, to make sure the bowls conform to the World Bowls Master Bowl test. The bowls are then adjusted on the lathe, if found to be under or over biased, but this is very rare occurance, due to the accuracy of the compuerised lathes that are now used.
Step 7. After this important test the bowls are then placed in a big drum filled with silocone chips, the drum gently rotates, gently polishing the bowls to a high gloss finish.

Step 8. Then comes the engraving, a lazer machine then engrave all 4 bowls at the same time according to a pre-loaded programme, the bowls are sent to the paintshop for painting. A further table test is then carried out to check against the World Bowls Master Bowl, after which the bowls are then packaged and ready for sale.

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