All references for lead screws in DINGS have following characteristics.
- Lead Screw Material
- 303 Stainless precision cold rolled steel
- Screw Coating
- Teflon coating is optional
- Standard Screw Accuracy
- 0.0071 inch/foot (0.18mm/300mm)
- Screw Straightness
- 0.08 inch/foot (6.66mm/Meter), measured as Total Indicated Runout (TIR). All screws are carefully checked for straighness before shipment.
- Screw Efficiency
- From 35% to 85% dependent on lead. Also depends on the usage of an Anti-Backlash nut with screw. The larger lead, higher efficiency of screw.
- Operating Temperature
- -20°C to +50°C
- Storage Temperature
- -20°C to +50°C, Keep in dry.
- Screw Backlash
- 0.01mm~0.1mm, depends on different lead. Anti-Backlash nut should be considered for high bi-directional positioning repeatability.
- System Backlash
- Includes screw, motor and attached mechanics. This will be the sum of all backlash in customer's motion axes.
- Nut Material
- Polyacetal or Polybutylene with lubricating additive. Standard is a free-whelling nut (Anti-backlash nut is available)
- Wear Life of Screw and Nut
- Depends on load, speed, duty cycle and environmental factors but typically it is ≥ 5 Million cycles.
- Special Note
- DINGS' Linear systems are manufactured from high quality materials. Because of variable effects of friction, lubrication and cleanliness, exact life cycle can not be predicted.
STEP 1 - CHOOSING A MOTOR SIZE (FORCE REQUIREMENTS)
Here is a general overview of the Output Thrust vs. Motor Size:
In a mobile environment, you can move left and right to see the contents (tables).
hybrid stepper linear actuators
||Recommended Load Limit(N)
|Hybrid stepper linear actuators
STEP 2 - CHOOSING A SCREW LEAD (FORCE AND SPEED REQUIREMENTS)
After estimating the required thrust and choosing a motor size that may fit your application, the speed and acceleration of the load must be considered and evaluated to choose and appropriate screw lead.
Due to the nature of lead screws, the output speed and output thrust achievable by a motor/lead screw combination are two proportional. increasing the required thrust will lower the achievable speed for a motor/lead screw combination. Therefore, the maximum output force of a system is lowered for applications that requires higher speed.
For complete motor/lead screw selection data, please refer to the Speed vs. Thrust curves for each motor size.
Although these two steps provide a solid foundation in motor/lead screw selection, other variables must also be considered:
- Duty Cycle
- Desired Life of a System
- Environmental Considerations
- Positional Repeatability
- Acceptable Backlash
- Acceleration / Deceleration
- Vertical or Horizontal
Because of the numerous variables involved in motor selection. We highly remommended for users to proceed with physical testing to accurately determine the motor/lead screw combination required for a given application.
One of the most common methods of moving a load from point A to point B is through linear translation of a motor by a mechanical lead screw and nut.
This section is here to assist and refresh your understanding of the basic principles of lead screw technology. Some basic design consideration are as follows:
- 1. What is the load of your system?
- 2. What is the required linear speed?
- 3. What is the distance to be travelled?
- 4. What accuracy does your application require?
- 5. What is the required time to move from point A to point B?
- 6. What repeatability does your application require?
- 7. Orientation is Horizontal or Vertical?
Although this section aims to provide a rough guideline to select a motor/lead screw combination that best fits an application, we recommend to contact our application engineering staff or sales representatives for further assistance with the motor selection process.