Pre-Sales Support Archives

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 other options are available:

1. E-Type Mounting Plate Assembly.

Bonding of Visiport VP220.B5 models with two-component urethane adhesive and a special VHB bondset. First the unit is bonded in the standard recommended fashion, i.e., using a vacuum pump to create a good seal with the VHB portion of the Mounting Plate Assembly. After this step is complete, a two-component urethane is injected into special cells in the bondset until they are filled. A supplied expansion tube captured excess urethane during curing. Once cured the injection tubing is removed, and the Visiport is bolted to the mounting plate as in standard V-Type installation using the six nylon coated screws. An E-Type mounting can be ordered using Model Order Code Suffix E, e.g., VP220.B5.E.

2. D-Type mounting. A bolt-on style of mounting for use with polycarbonate

Field installation using this method are only possible with polycarbonate (PC) windows. A bolt-hole pattern to accommodate 6 each 4-40 mounting screws must be drilled into the PC window in the desired mounting location. From the outside of the window, screws of the appropriate length are then theaded into the units mounting holes on the inside of the window, capturing a thin metal washer on the outside.Sealing is accomplished by capturing an o-ring between the inside surface of the PC window and the Visiport unit in a machined gland. A D-Type mounting can be ordered using Model Order Code Suffix D, e.g., VP220.B5.D.

If your application requires the use of non-standard mounting methods, please contact us. We can help you determine which one of the possible mounting methods is best suited to your application.

The typical Visiport® retrofit installation to a new or existing machine tool consists of specifying 4-6 discrete parts, and evaluating optional connection fittings, disc coating, and the machine tool window itself.

Discrete parts required for complete installation

1. Visiport® Base System

Includes Base Unit, Standard Mounting Plate Assembly, Bulkhead Assembly.

2. Conduit
Goes between "Installation Point" on window and "Bulkhead Point" on sheet metal.
Required not just to exit the conductors from cabin, but also to aspirate the Visiport.
Aspiration required to prevent fogging and overcome any disc pumping action.
Comes standard with matched length (conduit+8" prox.) of 2-conductor wire harness.
Sold in unit lengths, i.e., 1.5-m takes 2.0-m price point.

3. Fitting
Attaches conduit to Visiport base (and bulkhead assembly).
Priced as 1 part (T2K supplies 2nd matched fitting for Bulkhead Assembly end).

4. Power Cable
Goes between "Bulkhead Point" and "Power Supply Point".
Robotics-grade 3 conductor (2+ground) cabling.
Sold in unit lengths, i.e., 1.5-m takes 2.0-m price point.
Also sold in legacy 10-m length (Code P or P/N 220A7015).

5. Power Supply [option]
Required if machine does not have 5 amps, 24VDC to dedicate to unit.
Visiport® consumes only 200mA under no-load conditions.
When used with high-pressure coolant, Visiport® draws up to 4.8 amps.
T2K power supply is UL508 compliant with UL/TÜV/CE approvals.
Alternately, customer may supply own fully-regulated 120W power supply.

6. Installation Vacuum Pump [option]
One-time purchase for installers of Visiport & DiscAir systems (reusable).
Used to quickly and completely adhere standard VHB adhesive to substrate.
Helps installer identify color-shift in adhesive that had 'made' to substrate.
Comes with 4-40 & M4 thread adapters for T2K Mounting Plates/Bases.

Additional options and installation evaluation steps:

Optional Connection Fittings
When considering the necessary parts to make connections between the "Installation Point" and "Bulkhead Point", and between the "Bulkhead Point" and the "Power Supply Point" span distances, there are 90° Strain Reliefs and Adapters available for the Terminal Box bulkhead assembly that allow you to modify the plane that the Conduit and Power Cable will drape in, to allow for smooth opening of doors and windows to which the Visiport® system is installed. Please refer to the price sheet for price and part number details.

DLC
Diamond-like carbon (DLC) coating is an option for the glass disc supplied with the Base Unit. The few atoms deep layer provides exceptional scratch resistance and lubricity to the regular chemically strengthened glass used. This coating is popular with aerospace machining operations, but it sufficiently costly that T2K advises customers to evaluate the standard disc's life under operating conditions prior to making the 2X cost to 5X plus wear calculation. Please note that the coating does not impart any additional impact resistance to projectiles, as the coating is only several atoms thick.

Machine Tool Window Evaluation
Finally, there are several issues regarding the condition of the machine tool window that must be considered by the Visiport® installer in order to ensure a successful installation. The window must not be so scratched as to prevent proper viewing through the window. The Visiport® does not replace the existing window, it augments the window that is already there. Merely installing a Visiport® system over a scratched up window will not provide the desired visibility.

Secondly, the windows installed into machine tools are of two types, namely polycarbonate plastic or a multi-layer machine tool safety window composed of a glass layer on the wet side of the window for scratch resistance to chip activity together with a polycarbonate plastic layer for impact resistance, either with an edge seal or metal frame for containment and mounting. Machine tool safety windows that meet clarity requirements can be easily cleaned up to allow very successful bonding of the VHB adhesive that is used in the standard VHB Mounting plate.

Polycarbonate windows are another story, in that chip activity and oil contamination are typically such that the window found on a machine tool in use cannot be cleaned sufficiently to accommodate bonding of the VHB adhesive. While 3M's VHB adhesive is tremendously strong, it needs to bond to the window substrate rather than to a thin film of oil on the surface of the substrate, and due to the wetting action of modern metalworking fluids, together with the scratches and pitting common to chip activity, a used window must be considered contaminated and should thus be replaced at the same time a Visiport® installation is done.

As a customer service, T2K can easily provide you with a replacement polycarbonate window of any given size and thickness, with or without a hole pattern, and can also provide premounting of the VHB Mounting plate in a specified location to speed the installation process. Given the necessary dimensions, T2K can also provide custom aftermarket machine tool safety windows from SEGE, the world's leading manufacturer, with full CE Mark impact class requirements, at an extremely competitive cost.

With machine tool windows having been classified as a wear item in some countries that should be periodically replaced to prevent metalworking fluid embrittlement over time, T2K would strongly recommend that customers consider replacing any machine tool windows that are blind, cracked, severely pitted, or over 5 years old. Research has found that over 8-10 years, some polycarbonate windows had as little as 10-15% of their original impact strength, due to the exposure to metalworking fluids, and that it was impossible to visually determine which windows had been embrittled simply by visual inspection. The ease of replacing these windows, and the ease of maintaining you Visiport® installation on your machine tool window, should help to improve operator safety and productivity at the same time. Please contact T2K for more information.