TMC’s CleanTop^® II Steel Honeycomb Optical Top is the industry standard. It provides the highest core-density and smallest honeycomb cell area in an all-steel construction with the first, and still best, spill-proof hole design.

CleanTop^® II improves upon the first spill-proof optical top design, patented by TMC in the 1980s. The new process yields a cleaner, more precise, and more corrosion-resistant set of tapped holes.

Perhaps no single characteristic of an optical top is as crucial as its structural damping. TMC’s R&D Department is constantly evaluating new techniques and materials to maximize structural damping performance. We are now able to offer new, improved levels of performance and added flexibility in specifying a TMC top.

Radius corners and non-magnetic tops are among the other improvements and additions to our product line.

TMC’s CleanTop II Optical Top is the latest and best method yet for providing a spill-proof optical top with unmatched structural performance. CleanTop^® II is now a standard feature of all TMC optical tops. Conventional open core tops are no longer made by TMC.

Our innovative CleanTop was the first spill-proof optical top. Its patented design involved capacitance discharge welding a one-inch-long stainless steel or plated steel cup under each drilled hole prior to thread tapping. The key elements of the patent are that the cups are individual and non-load bearing.

CleanTop^® II improves on the original CleanTop design. Individual CleanTop^® II cups are epoxy-bonded, not welded, under each tapped hole after it is tapped and cleaned. Cups are made from chemically resistant nylon 6, and stainless steel (304 alloy) cups are also available as as option. Holes are now tapped and countersunk prior to adding the cups to allow the machined top sheet to be thoroughly cleaned with open, rather than blind, holes prior to bonding. The top plate is processed through a custom TMC industrial cleaning center where a high pressure, high temperature cleaning solution is forced through each threaded hole, completely clearing any machining or tapping debris. Several rinse and dry cycles ensure an essentially “sterilized” top surface prior to bonding the cups.

CleanTop^® II and the original CleanTop share the following features:

• Structural construction, specifications, and integrity.
• Liquid spills on the surface are contained and cannot reach the top’s honeycomb core.
• The core is completely clean and dry with no residual thread-cutting oils to out-gas.
• Extremely clean tapped holes make screw insertion smooth and simple.
• Easy retrieval of small parts dropped into the holes is assured.
• Since no penetration of the core is possible when dangerous chemicals are used on the top’s surface, health hazards will not occur by chemicals reaching the core unnoticed.
  
  

General Chemical Resistance of Nylon 6 and Stainless Steel 304 Alloy Cups (optional)

	Nylon 6	304 Stainless Steel
Aromatic Solvents	Excellent	Excellent
Aliphatic Solvents	Excellent	Excellent
Hydrocarbons	Excellent	Excellent
Gasoline & Oils	Excellent	Excellent
Refrigerants	Excellent	Excellent
Chlorinated Solvents	Fair	Excellent
Weak Acids	Good	Excellent
Strong Acids	Attacked	Excellent
Weak Alkalines	Excellent	Excellent
Strong Alkalines	Good	Excellent
Oxidizing Agents	Attacked	Excellent