This subject popped into my head when I was taking a shower the other day in a hotel whose bathrooms sorely need refurbishment. You know what it’s like when confronted with the type of shower that you adjust the hot and cold on to taste, achieve the perfect mix and then someone runs a bath and you either freeze or get boiled alive – it was one of those. I was left longing for a thermostatically controlled shower. Just set the desired temperature and it will deliver that no matter what while coping with changes in the supply. This is feedback in operation.

This is critical when winding delicate materials. Tension needs to be maintained but within strict confines otherwise material will tear or deform or cause blockages – all of which mean downtime and reduced productivity. The answer is a Closed Loop system including feedback mechanisms at all critical points. Depending on the need these may be either Load Cells or Dancer Arms. The former I would employ where the need is for a very responsive system and the latter where maintaining tension and positioning is key – for instance where the material is going to be perforated or slit in given lengths.

For these more sensitive and fragile web materials, about 25% of applications, I will run winders in Speed rather than Torque mode. Speed will remain constant while Torque is adjusted constantly.

Not so dissimilar to a thermostatic shower after all.

   
© 2012 Tim Oxtoby Ltd / Terms and Conditions