I am looking for a way to measure width of wood boards while traveling along a conveyor.
The widths can range from 3 to 11 inches.
I am thinking about installing a shaft encoder on the conveyor head shaft and a photo eye detecting boards from above while traveling.
The arduino controller will count the encoder pulses from the boards leading to the trailing edges and will determine the width.
Is there a better/easier way to do this?
Thank you
Describe the conveyer. Is there a small gap between two sections? How fast do the boards travel? The standard way to measure width is to momentarily clamp them to a fixture in the conveyer with a roller and measure from fixture to roller.
PAul
If the conveyor runs reliably at a fixed speed all you would need to do is time how long the wood was present. But yes more info and a picture would be useful.
@Paul,
Yes there is a gap between two sections, the speed is about 60m per minute.
The problem with clamping them with a roller is the wheel inertia (it will keep turning after boards cleared them).
@john
No the speed is not constant
abdelhmimas:
I am looking for a way to measure width of wood boards while traveling along a conveyor.
I know I am being picky but I would consider that to be the length. In my world vision the width is the measurement from one side of the conveyor to the other.
abdelhmimas:
The problem with clamping them with a roller is the wheel inertia (it will keep turning after boards cleared them).
Put a lightweight brake on the roller.
...R
Robin2:
I know I am being picky but I would consider that to be the length. In my world vision the width is the measurement from one side of the conveyor to the other.
Put a lightweight brake on the roller....R
Exactly my thought!!!!
The wheel rotation is not important. What you are measuring is the distance from the bumper to the wheel with the board trapped between the two for just an instant.
Paul
Sorry for the confusion,
This photo shows the travel direction with pushers.
The width is measured in the same direction than the conveyor.
Was thinking to put photoeye on top of the board and reading encoder counts on both edges.
Thanks
abdelhmimas:
Sorry for the confusion,
This photo shows the travel direction with pushers.
The width is measured in the same direction than the conveyor.
Was thinking to put photoeye on top of the board and reading encoder counts on both edges.
Thanks
You will have to explain that design in a whole lot more detail!
Paul
What kind of precision do you expect? Where is the photo?
Here is a sketch,
the boards can range from 2" (50mm) to 11" (280mm) wide.
they have nominal widths ( 2"-3"-4"-5"-6"-8"-11") no values in between.
so I guess I can set a table with minimum and maximum counts for each width.
Thank you
I grew up with saw mills. My father and my uncle both owned saw mills. So, I wonder why you do not know the board width at the time they are being sawn? They ALWAYS knew.
Paul
@Paul,
I want to measure the width, the thickness and the length of the boards while they run above the conveyor.
I figured out how to measure the length and the thickness.
This is an automated process, where the boards are fed randomly.
At the end of the shift, i want to know how many boards were produced (size sorted).
Thank you for that. I assumed they were all freshly sawn boards. I will have to think a bit.
Describe the design of the conveyor. Is it a belt or is it powered rollers or are is there a set of chain links that move the boards? What would happen if each board was stopped on the conveyor for perhaps one second and then let continue? This would happen for each board, so the gap between them as a whole, would not be changed.
Paul
Paul_KD7HB:
I grew up with saw mills. My father and my uncle both owned saw mills. So, I wonder why you do not know the board width at the time they are being sawn? They ALWAYS knew.
I think the OP is using "width" to refer to the thing your folks called "length"
...R
Robin,
In sawmills jargon the width is what I showed in the picture.
They define boards by thickness x width x length, i.e two by four x 8 which means 2 inches thick by 4 inches wide and 8 feet long.
I dont know how to explain more.
Paul
Yes, chains conveyor with pushers (lugs) at constant gap that pushes the boards through the conveyor.
Boards can stop of course, that why we need an encoder
I first thought it was width as it ran down the conveyor
it is length in regards to the conveyor, but width in regards to the board.
photo eye detects presence of board and end of board, leading edge and trailing edge.
exact speed of board times duration = distance.
roller speed during the timing period, no concern about freewheeling between boards.
abdelhmimas:
They define boards by thickness x width x length, i.e two by four x 8 which means 2 inches thick by 4 inches wide and 8 feet long.
I dont know how to explain more.
That is also my understanding. But I would illustrate it like this - which is 90° to the way you have it
...R
Robin2:
That is also my understanding. But I would illustrate it like this - which is 90° to the way you have it
You are right, only the boards are traveling 90 deg compared to picture you posted....R
dave-in-nj:
I first thought it was width as it ran down the conveyor
it is length in regards to the conveyor, but width in regards to the board.photo eye detects presence of board and end of board, leading edge and trailing edge.
exact speed of board times duration = distance.roller speed during the timing period, no concern about freewheeling between boards.
Thank you
The only issue I can think of concerning this design is when the board stops right underneath the encoder roller.
I think the suggested solution with shaft encoder installed on the conveyor drive is the best one: reading the counts between the leading and the trailing edges.
Thanks
abdelhmimas:
You are right, only the boards are traveling 90 deg compared to picture you posted.
I understand. I had not imagined that your conveyor was over 8ft wide.
But that raises another question in my mind - are you trying to build a system to measure the 8ft length or the 4inch width?
If it is the 4inch width that you need to measure then I presume your system is sawing panels into strips.
I hope you can see how a lot these questions would be unnecessary if you gave us a full description of the project.
...R