The Visiport and Discair product lines have been offered with 3M VHB adhesives as standard since their inception. 3M VHB (very high bond) adhesives have a number of advantages that have made it a good choice for most installations:
1. Excellent bonding to clean glass and polycarbonate window substrates.
2. Conformance to surfaces nearly 1-mm out of flatness.
3. High resistance to water soluble coolants at correct pH.
4. Excellent vibration resistance characteristics.
There are applications, however, for which users have expressed a desire for bonding and application alternatives. Two options that are currently in early introduction include bonding of Visiport VP220.B5 models with two-component adhesives together with VHB, and a bolt-on style unit for use with polycarbonate. If your application may require the use of non-standard mounting methods, please contact us for details on the VP220.B5.E and VP220.B5.D configuration codes.
Bonding failures have occasionally occurred where customers have used synthetic or semi-synthetic cutting fluids at extremely low pH levels. A known problem with such coolants is their tendency to become caustic if not maintained carefully, allowing them to attack the interface between the Visiport aluminum base and the bonding material.
After simulating such conditions with low pH metalworking fluids, it seems that bonding failures of this type are due more to the fact that the caustic metalworking fluid has eaten the aluminum away from underneath the seal junction than from a failure of the sealing material itself.
Naturally, caution should be exercised when using coolant susceptible to such pH balance problems. In addition to damaging the Visiport installed in such applications, it seems highly likely that significant and costly machine tool component failures would be an eventual outcome from this type of situation. Coolant types based on water soluble mineral or natural oils would seem to be preferable under these conditions, and are eminently compatible with Visiport installations.
For more information, please contact T2K.
Avoiding Contact with the Spin Disc
Visiport spin window systems are rugged and safe. There have been no reports of accidents involving any spin window system we know in their 10 year history. As with any product, Spin Windows must be properly installed.
While we have no incidents on record where an operator has been injured due to contact with the spin disc, it is possible that some inadvertent contact may occur if the device is allowed to continue running while an operator or repair person enters the machine cabin during maintenance or repair of the machine tool. There are no sharp or protruding features on the spin disc that would injure anyone through contact.
T2K recommends that to avoid any possibility that hair or clothing could become entangled in a rotating spin disc, however, that the Visiport be switched off to avoid any such incidental contact.
All spin windows operate on the same basic concept, i.e., that a spinning disc catches the metalworking fluid and chips and spins them off to keep the viewing area clear at all times.
Wear Factors:
Depending on the type of material being machined, and the aggressiveness of the machining being done on a given piece of equipment, and the distance between the work are and the spin window, as well as a number of other factors, a glass spin disc will begin to lose it clarity and viewability over time.
This is due not only to the scratches and abrasion from chips, but also due to the surface interaction of evaporating metalworking fluids and the chemically-strengthened float glass itself. This is especially so in environments where calcium salts are used to prevent the foaming of coolant.
Finally, there are unintended influences such as tool breakage and projectiles such as inserts that will instantly degrade you viewing experience.
With such a large number of variables involved, there is no way for T2K to predict how long a spin disc will last in your particular application. Some aggressive applications, such a ceramic machining, will cause the spin disc to lose its clarity quickly, whereas other end customers have machined parts for nearly ten years and never replaced the disc assembly.
Replacement:
While we can make no prediction as to how long your disc assembly will last, T2K has designed the product to make the replacement of the disc assembly literally a two minute process, once you have acquired the appropriate replacement part. While we would recommend that all end user sites have at least one spare disc in stock to overcome broken discs due to tool failures, T2K maintains stock of all models of Visiport and DiscAir spin windows available for same-day shipment. For details, contact T2K at (800) 267-2120.