# Lead screw and frame calculations

• daz18983
In summary, the conversation is about seeking help with designing a system involving a lead screw to raise and lower a heavy object. The design includes a yellow bracket for support, a main body with guide channels and the lead screw, a slide with a rotating arm, and winkel rollers. The goal is to determine the appropriate size for the lead screw and ensure that all components can support the weight of 250kg. The individual is open to receiving instructions or formulas to analyze the structure and is willing to provide additional information if needed.
daz18983
Hi

I am new to the design game as it where and I have scoured books and the internet looking for calcs, examples, help with a design I am putting together which involves raising and lowering a heavy object using a lead screw. I know its not strictly CNC stuff but I believe someone may be able to help with the power screw/lead screw side of the design. I have attached images to aid in the understanding.

The system is straight forward, a yellow bracket which is hung supports the system and allows the system to slide left and right on Winkel Rollers. The main body of the system (in green) consists of a box section frame with guide channels and houses the lead screw. The screw is turned by an operator which raises and lowers the slide (shown in orangy-red) again using winkel rollers in the guide channels. The slide has a rotating arm (in cyan) which swings the wheel clear.

Basically I need to do some scoping calcs and I don't know where to start. Obviously at this stage the scoping is to make sure the design is actually feasible so its section sizes, lead screw size etc... and making sure its all not going to fail under load.

So I'm lookto make sure the channel and angle on the yellow bracket can take the load from the main body and wheel.

The box section, channel, platesm winkel wheels and lead screw can take the load of the wheel, slide and arm

The slide can take the load of the arm and wheel

The arm can take the load of the wheel.

I'm hoping you can help me calc the lead screw size. The lead screw is zzzmm long, trapazoidal thread (if this it he best) and is to raise and lower around 250kg. There is no desired speed of lowering/raising as the screw will be turned via handwheel or socket, either way the rotation will be provided by the operator.

Of course if you can help with any of the other sections that would be brilliant. For my attemt at the calcs I took the main body (green) in isolation and worked on the assumption is supported at the base and that the 250kg load is just acting in a linear fashion up and down the lead screw. (as per image 4)

I am not neccessarily looking for the answers but if the formula I require or some instructions on how I can quickly go about analysing the structure and get what I need, that would be great.

I also have a 3D PDF i can post - email as neccessary.

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sorry, I missed image 4 off.

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## 1. What is a lead screw and how does it work?

A lead screw is a type of mechanical screw that is used to convert rotational motion into linear motion. It consists of a threaded shaft and a nut that fits over the threads. When the shaft rotates, the nut moves along the threads, causing linear motion. This is commonly used in applications such as machine tools, 3D printers, and robotics.

## 2. How do you calculate the lead of a lead screw?

The lead of a lead screw is calculated by dividing the distance traveled by the nut in one revolution of the screw by the number of turns in that revolution. This can be expressed as lead = distance traveled / number of turns.

## 3. What factors should be considered when calculating the lead screw and frame dimensions?

The dimensions of a lead screw and frame are dependent on several factors, including the desired linear motion, the load being moved, the speed of the movement, and the accuracy required. Additionally, the material and design of the lead screw and frame should be taken into account to ensure adequate strength and durability.

## 4. How do you determine the torque required for a lead screw?

The torque required for a lead screw can be calculated by multiplying the force needed to move the load by the lead of the screw. This can be expressed as torque = force * lead. It is also important to consider factors such as friction and efficiency of the screw when determining the required torque.

## 5. Are there any common mistakes to avoid when calculating lead screw and frame dimensions?

One common mistake to avoid is not taking into account the effects of friction on the lead screw. Friction can significantly impact the accuracy and efficiency of the system, so it is important to factor it into calculations. Additionally, not considering the material and design of the lead screw and frame can result in a system that is not strong enough to handle the desired load and speed.

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