I would like to know what the dynamic force load is....

[haruspex]

The weight is assumed to be equally distributed over the whole plate.
So you are suggesting to treat the 3 bodies as 3 different rods with different lengths using the formula mL2/3

you could do that, but I don't think it will make enough difference to matter. There are probably other aproximations being made that are more significant, like the way the torque from the load decreases as the angle increases. (How did you measure the angular acceleration?)

 

[omarmorocci]

you could do that, but I don't think it will make enough difference to matter. There are probably other aproximations being made that are more significant, like the way the torque from the load decreases as the angle increases. (How did you measure the angular acceleration?)

For that I will make an excel document and formula that connects the angle to the torque of the load hence giving me different acceleration.
But for now it's just the initial position,

 

[omarmorocci]

What I am actually also confused about is how to calculate the dynamic load on point A ( pivoting point )
now that I know the acceleration should I just use the following formula
By - Ay - Wt cos tetha = mass * acceleration ?

given eveything is know , I should be able to calculate Ay , which is the dynamic load right ?

 

[haruspex]

What I am actually also confused about is how to calculate the dynamic load on point A ( pivoting point )
now that I know the acceleration should I just use the following formula
By - Ay - Wt cos tetha = mass * acceleration ?

given eveything is know , I should be able to calculate Ay , which is the dynamic load right ?

The problem with that formula is that not all the forces and accelerations are parallel. So it works as a vector equation (if you drop the cos theta) but not as a scalar one.
Choose two perpendicular directions to resolve the forces in (either vertical and horizontal, or parallel to the plate and perpendicular to the plate) and write one equation for each.

 

[omarmorocci]

The problem with that formula is that not all the forces and accelerations are parallel. So it works as a vector equation (if you drop the cos theta) but not as a scalar one.
Choose two perpendicular directions to resolve the forces in (either vertical and horizontal, or parallel to the plate and perpendicular to the plate) and write one equation for each.

I am talking about the tangential acceleration tangential acceleration = angular acceleration * radius
and I am resolving the forces in the direction of the plate and perpendicular to it ( The same as the Ax and Ay)

 

[Delta2]

What I am actually also confused about is how to calculate the dynamic load on point A ( pivoting point )
now that I know the acceleration should I just use the following formula
By - Ay - Wt cos tetha = mass * acceleration ?

given eveything is know , I should be able to calculate Ay , which is the dynamic load right ?

What you calculated is the angular acceleration $a$. The acceleration in your equation above should be $a_y$ which is equal $a_y=0.440a$

But there is also the $A_x$ component of the load which relates to the centripetal force and centripetal acceleration $a_x$ which doesn't relate to the angular acceleration, but it relates to the angular velocity $\omega$ it is $a_x=\omega^2(0.440)$ and it should be
$A_x+W_tsin(\theta)=M_ta_x$ , where $M_t$ total mass of 64kg.

The total load will be $A=\sqrt{A_x^2+A_y^2}$

 

[haruspex]

View attachment 103561
I am talking about the tangential acceleration tangential acceleration = angular acceleration * radius
and I am resolving the forces in the direction of the plate and perpendicular to it ( The same as the Ax and Ay)

Sorry, yes, I see what you are doing. As Delta² says, you need to consider Ax as well. However, I don't think you need to worry about centripetal acceleration. It will be insignificant.

 

[omarmorocci]

Excellent work guys. I will tidy up all the calculations and make less assumptions since now I know how to work it out.

One last question I have is how to I get the compressive pressure ?
http://www.igus.com/wpck/3726/iglidur_clipslager?C=US
Im looking to use these bearings, and I need to know the compressive pressure.
the static load on each bearing is approx 500 N
and dynamic load is approx 1100 N
the thickness of the sheetmetal is 2 mm

Thanks in advance

 

[Divya Shyam Singh]

Come in contact with someone from the company and talk to them. They usually have a software where you 'd have to enter your value. Trust me, they are better at selecting the right bearings for you. I tried doing the same calculations, got some values, fixated on some model of bearings, talked to their technical guy and it turns out that whatever i had done was all in vain.
You could also ask them to suggest you the right bearning model for your use.
Please do tell them the correct conditions in which the bearing is to be used. (like environmental conditions, loads, Life of the component that you want)
One important aspect is serviceability which basically means how often can you get the bearing serviced.

Try to get as much information regarding bearing as possible from the person you talk to. He will be more than happy to help.

Hope this helps.

 

[Nidum]

Before doing anything else work out whether your calculated acceleration figure gives you total motion time for the platen consistent with your practical observations .

 

[omarmorocci]

Before doing anything else work out whether your calculated acceleration figure gives you total motion time for the platen consistent with your practical observations .

I used excel to vary the angle and hence get different angular accelerations,
In real life, the anglar speed seems to be contant but I am not really sure how to confirm this since the whole motion is only about 20 degrees and in 1.5 seconds

 

[omarmorocci]

.

 

[Divya Shyam Singh]

First of all:
GOOD work with the calculations.
In real life situations, there are resistive frictional forces at every hinge point whose resistive moments have not been considered here.
Also, the actual force output of the actuator is less than the theoretical force given in the actuator manual etc.

One thing i wanted to bring into your concern is that since the angular acceleration is increasing constantly over the range of motion, there will be a "collision" at the end between Hinge at B and the upper most portion of the slot. Over the time, due to constant impact loads on hinge B might be deleterious.

 

[omarmorocci]

First of all:
GOOD work with the calculations.
In real life situations, there are resistive frictional forces at every hinge point whose resistive moments have not been considered here.
Also, the actual force output of the actuator is less than the theoretical force given in the actuator manual etc.

One thing i wanted to bring into your concern is that since the angular acceleration is increasing constantly over the range of motion, there will be a "collision" at the end between Hinge at B and the upper most portion of the slot. Over the time, due to constant impact loads on hinge B might be deleterious.

Thank you for your words,

Fortunetly, the collission does not infact happen as the pneumatic cylinder reaches it's maximum length before the shaft hit the end of the slot, so there is no damage there.

 

[Divya Shyam Singh]

May i ask where this component is currently used? what is it related to?

 

[omarmorocci]

May i ask where this component is currently used? what is it related to?

It is used in sorting packages for companies like DHL Fedex etc

 

[omarmorocci]

Come in contact with someone from the company and talk to them. They usually have a software where you 'd have to enter your value. Trust me, they are better at selecting the right bearings for you. I tried doing the same calculations, got some values, fixated on some model of bearings, talked to their technical guy and it turns out that whatever i had done was all in vain.
You could also ask them to suggest you the right bearning model for your use.
Please do tell them the correct conditions in which the bearing is to be used. (like environmental conditions, loads, Life of the component that you want)
One important aspect is serviceability which basically means how often can you get the bearing serviced.

Try to get as much information regarding bearing as possible from the person you talk to. He will be more than happy to help.

Hope this helps.

I believe there was some simple calculation to find the pressure ,
It is force/area but I am not sure on what area to take ( is it diameter * thickness)?

 

[Divya Shyam Singh]

No, actually i was talking about a project i worked on a few months back. Its always better to talk to them ask what all parameters do they require for them to be able to decide for the best bearing.
But yes, generally its Force/Area for deciding the pressure required from the actuator
I don't know about the bearings though. In my opinion it actually depends upon the bearing. In general maximum contact pressure is derived by using hertz law but there are a lot of other factors in play so its quite complicated when designing bearings for practical purposes.

 

[Nidum]

http://www.astbearings.com/technical-information.html