You will find several ways of applying rubber to a metal core so that you can manufacture a roller. Get a lot more information and facts about รับหล่อลูกกลิ้งยาง
By far the most common procedures are:
Wrapping a prepared calendared sheet of rubber around the core, that may be held between two points within a lathe.
Extruding an endless rubber strip and applying it to a slowly rotating core that's fixed among two points inside a spin station.
Sending the core by way of a cross head extruder, where the rubber is flowing round the core, as a result covering it.
Placing the core involving the rolls of a Three-roll-builder and covering it with an endless calendared sheet of rubber - a roll of which is placed within the Three-roll creating machine.
You will discover positive aspects and disadvantages to every of these solutions and particular situations where one may very well be preferable to a further.
1. ‘Traditional’ wrapping
The ‘traditional’ wrapping begins with cutting the rubber sheet as outlined by the desires from the roller (width and diameter) and placing the prepared core into the lathe. The core is turned slowly because the rubber sheet wraps around it.
Based on the diameter necessary plus the geometry from the calendared sheets this wrapping must be repeated a number of occasions. Immediately after reaching the final diameter (plus overbuild) a bandage can be wrapped about the roller within the exact same machine for curing purposes.
This method is inexpensive and valid for rollers of a medium size each in length and diameter. It is actually flexible and, provided a roller of 1500 x 500 mm, requires roughly 15 minutes covering time like all set up and handling work.
Within the case of series production this method doesn't deliver any possibilities of price reduction. In addition, it requires calendared rubber sheets, which are far more expensive than rubber batches.
Care need to be taken as the connecting line in between two rubber sheets and also the lack of pressure that sticks the rubber for the core and itself, usually causes air bubbles. On account of the reasonably low investment required, this wrapping strategy is used in almost each and every start out up company.
2. Extrusion method
When compared with traditional wrapping, the strip extrusion method supplies quite a few advantages. Firstly there is absolutely no really need to make use of the more highly-priced calendared rubber; batches which can be fed for the extruder are enough.
Secondly there is absolutely no limitation within the roller size. This technique can be used for any roller width and diameter and it can be the only productive method to cover large paper mill rollers.
Thirdly there's no setup time for distinct rollers so long as identical compounds are used; changing width and diameter don't impact the process at all.
What’s additional the compound remaining inside the machine or reduce away at the ends with the roller just after wrapping might be used again with no additional treatment.
It’s also possible to cut down the wrapping time per roller by 10 to 20%, with staff preparing the subsequent core while the process continues. And finally, the reject price can be cut down to about 50%.
You can find, even so, some disadvantages. Due to the fact that the compound applied for the roller tends to flow towards the ends, overbuilds of as much as 16 mm (around the diameter) is essential.
Significant investment - as much as ten instances larger than for classic wrapping - and highly skilled personnel are also required. On average it requires a worker six to twelve months’ training to develop into an expert in extrusion.
In spite of the improvement in rejects, there are actually nevertheless two % or more of rejects attributable to air bubbles. Undoubtedly there is a gain in flexibility and price reduction, but strip extrusion is just not the final solution in rubber roller covering.
3. Cross head extrusion
For series production - beginning with plenty of 15 - 20 identical rollers and quantities in excess of one hundred rollers with identical compound - cross head extrusion can be a excellent alternative.
Additionally, it uses inexpensive rubber batches and may lower the covering time per roller (1000 mm wide) to about 2 minutes. Even though at the least two, generally 3, workers assistance the process, the personnel time per roller can be cut down to 5 - 6 minutes, one third in the time expected for the methods pointed out above.
While the benefits are clear, crosshead extrusion is not a well-known decision for roller makers. The primary cause is definitely the wide array of unique rollers manufactured by the average roller covering company in combination using the little quantity of identical rollers. You'll find also diameter limitations with the crosshead extruder.
Furthermore these machines price far more than £200.000 GBP and small or start-up companies can rarely afford such an investment. The capabilities necessary are also far beyond the average information of roller covering. Even experienced companies meet new challenges with this approach from time to time.
