Occasionally, our engineering team receives inquiries from customers asking for a “Teflon screw.” While creating a lead screw entirely out of Teflon (PTFE) would result in a part that is too soft to transmit power, what these customers are actually looking for is a Teflon Coated Stainless Steel Lead Screw.
This specialized surface treatment transforms a standard linear stepper motor into a high-performance component suitable for the most demanding clean environments.
Here is why you might want to consider adding a Teflon (PTFE) coating to your next linear actuator.
1. The Power of “Dry Running” (No Grease Required)
The single biggest advantage of a Teflon coating is that it eliminates the need for grease or oil.
Standard stainless steel screws require wet lubrication to prevent wear. However, in many applications, wet grease is a liability:
- Laboratory Automation: Grease can contaminate sensitive blood samples or chemical reagents.
- Paper/Textile Processing: Oil can drip onto the fabric or paper, ruining the product.
- Dusty Environments: Wet grease acts like a magnet for dust and debris, turning into an abrasive paste that grinds down the nut.
A Teflon-coated screw provides a permanent, dry lubricating layer. The nut glides smoothly over the surface without a single drop of oil, keeping your machine clean and maintenance-free.
2. Friction Reduction and Efficiency
PTFE (Polytetrafluoroethylene) has one of the lowest coefficients of friction of any solid material. By coating the 304 stainless steel screw with PTFE, we significantly reduce the drag between the nut and the screw.
Lower friction means two things for your motor:
- Less Torque Required: More of the motor’s power is converted into pushing force rather than overcoming friction.
- Longer Life: With less friction comes less heat and less wear on the plastic nut, significantly extending the operational lifespan of the actuator.
3. Corrosion Resistance
While 304 stainless steel is already resistant to rust, a Teflon coating adds a second layer of defense.
In applications involving harsh chemical vapors or saline solutions (common in medical analyzers), the PTFE layer acts as a barrier, preventing corrosive agents from directly contacting the metal surface of the screw.
Visual Identification
You can easily identify these screws by their color. While standard screws are shiny silver:
- Black Coating: typically indicates a standard PTFE mix for general friction reduction.
- Green or Grey Coating: often indicates high-end formulations tailored for specific wear or load characteristics.
When Should You Choose Teflon Coating?
While it adds a small cost to the actuator, a Teflon coating is the engineered choice for:
- Medical Devices: Where hygiene and sterility are non-negotiable.
- Pipetting Robots: Where splashing grease could ruin an experiment.
- 3D Printers: To prevent Z-axis binding without attracting filament dust.
Summary
A “Teflon Screw” is actually a precision stainless steel screw enhanced with a PTFE coating. This upgrade allows for dry operation, reduces friction, and extends the life of your linear stepper motor. If your project requires a clean, maintenance-free solution, ask the AKT Motor team about our coating options.