You will discover various ways of applying rubber to a metal core to be able to manufacture a roller. Get much more data about ลูกกลิ้งยางอุตสาหกรรมทุกชนิด
The most widespread approaches are:
Wrapping a ready calendared sheet of rubber around the core, that is certainly held involving two points inside a lathe.
Extruding an endless rubber strip and applying it to a slowly rotating core that is fixed in between two points in a spin station.
Sending the core through a cross head extruder, where the rubber is flowing round the core, hence covering it.
Placing the core among the rolls of a Three-roll-builder and covering it with an endless calendared sheet of rubber - a roll of which is placed inside the Three-roll creating machine.
There are advantages and disadvantages to each and every of those procedures and specific situations exactly where one could be preferable to another.
1. ‘Traditional’ wrapping
The ‘traditional’ wrapping starts with cutting the rubber sheet as outlined by the requires with the roller (width and diameter) and putting the prepared core into the lathe. The core is turned gradually as the rubber sheet wraps about it.
Based on the diameter required along with the geometry with the calendared sheets this wrapping must be repeated numerous times. After reaching the final diameter (plus overbuild) a bandage is usually wrapped around the roller inside the identical machine for curing purposes.
This method is low-priced and valid for rollers of a medium size both in length and diameter. It's flexible and, offered a roller of 1500 x 500 mm, requires roughly 15 minutes covering time such as all set up and handling work.
In the case of series production this method does not offer any possibilities of expense reduction. Additionally, it requires calendared rubber sheets, which are more pricey than rubber batches.
Care will have to be taken as the connecting line involving two rubber sheets and also the lack of pressure that sticks the rubber to the core and itself, usually causes air bubbles. As a consequence of the fairly low investment necessary, this wrapping method is used in almost each commence up company.
2. Extrusion method
In comparison with classic wrapping, the strip extrusion method delivers various benefits. Firstly there is no ought to use the far more pricey calendared rubber; batches which can be fed towards the extruder are adequate.
Secondly there isn't any limitation in the roller size. This approach may be used for any roller width and diameter and it is the only productive method to cover large paper mill rollers.
Thirdly there is absolutely no setup time for distinct rollers as long as identical compounds are used; altering width and diameter usually do not have an effect on the process at all.
What’s extra the compound remaining inside the machine or reduce away at the ends in the roller following wrapping is usually used once again with no added treatment.
It is also doable to lower the wrapping time per roller by 10 to 20%, with employees preparing the next core whilst the process continues. And lastly, the reject rate is often cut down to about 50%.
There are, however, some disadvantages. Resulting from the truth that the compound applied towards the roller tends to flow for the ends, overbuilds of up to 16 mm (around the diameter) is required.
Important investment - as much as ten times greater than for standard wrapping - and very skilled personnel are also necessary. On typical it requires a worker six to twelve months’ training to develop into an expert in extrusion.
Despite the improvement in rejects, there are still two % or additional of rejects caused by air bubbles. Undoubtedly there is a get in flexibility and expense reduction, but strip extrusion just isn't the final solution in rubber roller covering.
3. Cross head extrusion
For series production - beginning with a lot of 15 - 20 identical rollers and quantities in excess of one hundred rollers with identical compound - cross head extrusion is really a amazing alternative.
It also uses low cost rubber batches and may decrease the covering time per roller (1000 mm wide) to about 2 minutes. Even when no less than two, commonly 3, workers support the process, the personnel time per roller might be cut down to 5 - 6 minutes, one third in the time needed for the strategies mentioned above.
While the advantages are obvious, crosshead extrusion is just not a well-known selection for roller makers. The main purpose is the wide selection of distinctive rollers manufactured by the average roller covering company in combination with all the compact amount of identical rollers. There are actually also diameter limitations with all the crosshead extruder.
Furthermore these machines expense far more than £200.000 GBP and small or start-up companies can hardly ever afford such an investment. The abilities required are also far beyond the average information of roller covering. Even skilled companies meet new challenges with this technique from time for you to time.
