Hello all and thanks in advance for your time.
I'm a total newbie.
I want to build an automated procedure without doing complex programming.
Ideally I would like to have:

1 linear actuator (LA1), a rotating motor (RM1) and 3 limit switches (SW1, SW2 and SW3) -> SW2 & SW3 should have a double role. Actuator and motor should have a manual controller.

-Start button is pressed.
-LA1 starts the travel from the position of SW1 and travels till it reaches SW2.
-SW2 triggers LA1 to start to travel back and at the same time triggers RM1 spins at the specified travel setting
-LA1 reaches SW1 position

and that's one cycle

when x cycles are completed the mechanism will reach SW3 position
-that triggers both LA1 and RM1 to stop

Am I dreaming or is the double role possible without special programming?

Thanks again!

 

You description is very confusing, which is likely part of your problem

You talk about RM1 spinning at the specified travel setting? What does this mean? What determines this specified travel setting? What happens when RM1 reaches it? Stop? Keep spinning?

You talk about "the mechanism" reaching SW3, but this is the only mention of this "mechanism". What causes it to move? Where does it start from? How does it get to the start position, whatever that is?

Your description has LA1 starting it's travel from the position of SW1 to SW2 and back to SW1. What does it do when it reaches SW1? Stop? Go back to SW2 again?

Try giving a very clear description of your mechanism and how it behaves in response to the two actuators moving.

 

Hi WBahn, thanks for your reply.
I thought giving too much info would be confusing, apologies.
Imagine a woodworking panel saw station for sheet goods (plywood). Operation starts from the top and stops in the bottom where the sheet good has been cut.

The saw handle is attached to the linear actuator which moves horizontally and performs the cut.
Once the saw moves forward and reaches SW2 then it starts to move back while also the rotating motor is spinning a tiny bit.
The rotating motor is attached to a threaded rod, threaded on the rod is a base where the linear actuator + saw is attached.
That tiny turn pushes the mechanism to the bottom ever so slightly.
Meanwhile the linear actuator finished the back travel and reached SW1 so starts the travel forth and cuts the sheet good again.

After the cycle is completed x times, the mechanism moved to the bottom position where it meets SW3. That should kill the whole operation.

Does it make more sense now? Sorry this is my first build and have a lot to learn

 

That makes a lot more sense.

A couple of clarifications -- what controls how much the rotating motor turns on each cycle?

Also, what prevents the saw from binding as it is moving backwards at the same time it is moving downward against the material being cut?

It would seem, based on the limited knowledge we have thus far, to make more sense for the saw to travel back to the starting point and, upon reaching it, being moved downward the small amount and, if SW3 is not activated, making another cut.

 

Hi, thanks again.
Say the travel of the saw back is set to take 2 seconds. I was hoping that the rotating motor comes with a controller that can make it with a simple setting, first once SW2 is triggered to have a delay of 1 sec and then turn ever so slightly for another 1 sec.

The saw which cuts on the travel forward is angled forward, therefore when it travels back, the gap with the sheet good widens therefore there is no chance it will bind. Also assume the saw is much more sharp than the task at hand and handles the cut easy

 

Welcome to AAC.

First of all, you have already created a problem unrelated to the one you are trying to solve with the “no complex programming“ constraint. You need to discard that. If your problem is complex, complexity is needed to solve it—if not, it won’t be needed in a good solution. By attempting to short circuit this you are creating a situation where you can expect a bad solution.

Second, this project has serious health and safety concerns. These should be primary in the thinking about a solution and in the design that comes from it. Both the spinning saw blade and the linear actuator present very real dangers to people around the machine. Both mechanical and electronic safety mechanisms are a mandatory component.

Third, don’t specify parts of the solution before you understand the whole problem. For example, you have decided on a linear actuator before even investigating what it will have to do.

Start with writing out a timeline. Work out how long the saw will travel during the cut, and how long it will take to return. Draw out a timeline with each operation that must be performed at its appropriate spot.

Measure the force needed by the saw to make the cut, and to be returned to the starting position. These will be critical in selecting components. Measure the distances that will be traveled by the saw. These will be needed to select components.

A linear actuator might seems like a good choice, but I suspect that you will run into problems with size. There is also the real concern about safety and unforeseen circumstances that will lead to the actuator fighting against an object or something else in its path.

I would be inclined, in the absence of more information, to use a gravity-based solution allowing the saw‘s cut to determine it’s forward progress, and a return motor to pull it back down with the saw is not operating. No matter what, though, you will need an E-Stop, and some kind of sensing to ensure that things haven’t gone pear-shaped. An open loop solution is a danger to people and property.

As far as “complicated programming”, trying to do this without using modern options like PLCs or microcontrollers is going to be a lot more complicated in the end, and also potentially impossible to get quite right. Don’t write off the “smart” path before you understand what will be needed—particularly in this case where severe injury is a real possibility.

 

so called smart relays (mini PLCs) are created for small projects like this.
zelio, logo, alpha....

personally i would consider ClickPLC:
https://www.automationdirect.com/ad.../click_plcs_(stackable_micro_brick)/plc_units

 

PanicMode has delivered the same advice that I would suggest. And certainly the system can be automated, but more certain it will not be quite that simple.
In addition, all of the safety concerns mentioned by "Y" are valid, even if this setup is for a one-person shop.
So in addition to the controls mentioned it will also need a bit of safety interlocking and an emergency stop control. In some parts of the world safety does not matter, I do not offer complete designs for those areas.