# Lead Screw model in Creo and calculations

• inamukak
In summary, if the base plate is firmly attached to the ground then the lead screw will only deflect vertically, but if the base plate is not firmly attached then the lead screw will deflect in all directions. This will lead to failure of the L-shaped support holding the lead screw and the lever.
inamukak
Hi

I'm trying to make a lead screw in Creo which would be used to move a 400lb load linearly along the ground. This would be turned manually using a lever as shown in the pic (not the complete model). I have used a lead screw with a major diameter of 1 1/4 and determined the torque to move the load would be around 36.70 lb-in. What I'm unable to determine is the speed at which this would move the load a total distance of 3 feet, and if it would be possible to change this speed so that the lever doesn't have to be turned for quite a lot of time. Any help would be appreciated.

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Welcome to the PF.
The diameter of the lead screw is not the important parameter, you need to specify the pitch of the screw thread.
That will tell you how far the load will move for each turn of the crank handle, (your lever).
The speed you turn the crank will decide the speed the load moves.

Hi

Thanks for the reply. I took a TPI of 4 and etermined the torque required to move the load. I was basically looking for a way to related the RPM and the linear velocity, which I have figured out now.
Also, I'm trying to determine the fail conditions for the L-shaped support holding the lead screw and the lever, but I have no clue where to start. I've been trying to run simulations in Creo to determine this but to no avail. What stresses and strains should I take into consideration? And how will a force or torque on the lever lead to failure of the support?

Thanks!

If you assume the base plate is firmly attached, then only the vertical part of the mount will deflect when an axial force is applied by the lead screw. That will bend the material that is between the base and the lead screw. When the material bends the screw will be misaligned in the thread which will have other implications.

1 person
Thanks for the answer! I decided to perform the analysis in Workbench instead of in Creo and did manage to get some results from your answer.

Thanks again!

## 1. What is a Lead Screw model in Creo and what is its purpose?

A Lead Screw model in Creo is a virtual representation of a mechanical screw that is used in various engineering designs. Its purpose is to provide a detailed and accurate visualization of how the screw works and its dimensions, which aids in the design process.

## 2. How does Creo calculate the dimensions and parameters of a Lead Screw model?

Creo uses mathematical formulas and algorithms to calculate the dimensions and parameters of a Lead Screw model. These calculations are based on the screw's pitch, lead, diameter, and other relevant factors to ensure accuracy and consistency in the model.

## 3. Can I customize the calculations for my specific Lead Screw model in Creo?

Yes, Creo allows for customization of the calculations for a Lead Screw model. Users can input their own values for parameters such as pitch and lead to create a model that fits their specific design requirements.

## 4. How does Creo handle different types of Lead Screw models, such as acme threads or ball screws?

Creo has a variety of built-in features and options to handle different types of Lead Screw models. Users can select the specific type of screw they want to model and input its unique parameters to accurately represent it in their design.

## 5. Can I simulate the movement and functioning of a Lead Screw model in Creo?

Yes, Creo has simulation capabilities that allow users to see the movement and functioning of a Lead Screw model in action. This feature is particularly useful for testing and optimizing the design before it is physically manufactured.

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