Page 46 - TNB 2024-1
P. 46

The Retreading Process and the Importance of MS224 Certification 轮胎翻新过程和MS224认证的重要性 Many readers may be unaware of of exactly how a a a a a a a a a a a retread is manu- factured so in in order to avoid the plethora of misinformation about retread- ing ing in in in in our third article on on on this subject we focus on on the manufacturing process There are in in in in fact fact two distinct methods of manufacturing retreaded these being known as hot cure cure cure cure or or mould cure cure cure cure on on on the the one hand and and cold cure cure cure cure or or precure on on on the the the the other The difference between the the the the two processes lies in in in how the the the the the the tyres are built and cured so the the the the beginning of the the the the pro- cess cess is the the the same for both processes Using casings are first collected sorted by size and inspected for damage to make sure the tyres can be safely retreaded This is is is generally carried out by trained personnel who inspect the tyre tyre visually However tyres may also be checked by tyre tyre testing equipment equipment such as nailhole detectors or or shearography equipment equipment The old tread is is then removed from the the casing using a a a a buffing machine This 46 truck & bus news 2024/1 process reveals minor injuries which are repaired using air air buffers buffout tools hand buffer buffer and and brushes in in in a a a a a a a a pro- cess cess known as skiving The hole creat- ed ed during this process are then filled in in in in with rubber using a a a hand held extruder gun At this point the the two processes di- verge Following cementing in in in in in the the the hot cure cure process the the the prepared casing is covered with uncured rubber and then cured cured at at 150-160 C in in a a a a a a a mould similar to that used in in in the new tyre manufac- turing process In the the cold cure/precure method a a a a pre- cured tread tread strip is applied to the the the tread tread area and then sealed in in in a a a a a a a a a a a vacuum in in in a a a a a a a a a a a rubber envelope before being cured at 100-115 C in an autoclave Under both processes the the tyres are then subjected to to a a a a final inspection before be- ing sold into the market The MS 224 Retreading Standard Retreaders in in in Malaysia are subjected to stringent guidelines on the the the material used used and the the the process used used in in in the the the manufacture of retreaded tyres TRMAM the Tyre Retread Manufactur- ers ers Association of Malaysia points out that “tyre liners have to to conform to to reg- ulations set out by the Department of Standards Standards Malaysia (Standards Malay- sia) specifically MS 224:2005 as certi- fied by SIRIM QAS International International which is part of The International International Certification Network which gives these products ac- cess to 37 national markets by meeting these standards ” The Standard specifies the the require- ments for the the retreading of pneumatic tyres classified under C1 C2 and C3 categories It covers the the definitions of terms used fin in in in in in the the the retreading industry initial inspection criteria criteria for for the the the rejection of of casings acceptance criteria criteria for for for the the repair of of of tyres for for retreading retreading in-process retreading retreading guidelines inspection of of the finished tyres quality control testing 

   44   45   46   47   48