Prograaming Flow Pack Machine

Hi,

I'm working on a flow pack machine, it has got all the mechanical parts and the sensors and the actuators with an HMI/PLC Which I can't access, and it's working,
but I want to change the hmi and to add a plc And I have to make a prg to have the same function ,
I managed to make a little plc program to read all the sensors and the encoder value and to cmd all the motors, but I don't know how to synchronize between the film cutter and the film.

I have a VFD that runs the film cutter (it's a rotary resistor which cuts and seals the product package) and a potentiometer to adjust the speed of the VFD and an encoder attached to the chain of the film cutter
and I also have a servo motor which pulls the film and I control the position and speed of this Servo from the plc
I don't know how to synchronize between the speed of the film cutter (VFD) and the speed of the
film (Servo drive) so I could have the same length of the product in all speeds

I also have an eye color sensor, and I don't know what to do when the eye color sensor detects the eye mark in the film.

Any help appreciated ,

So, your application is rotary cutter with roll to roll and color mark. It is far from easy and requires experience.
Do you have "dancer"?
Do you have force sensor?
Force or speed control?
I think you should have a least one more drive - at least three in total (winder, unwinder, cutter).
More info is needed, maybe some sketch.

yes and I know that it's not easy and actually I'm still learning plc programming with less than 2 years of experience in plc programming and building management systems

I don't know what dancer is and I don't have force speed sensor
and the vfd that runs the cutter it also runs the winder or unwinder
there's a lot of chains and gears for mechanical transmission
and the servo driver controls 4 rotary parts which pulls the film and a tensioner , and the speed of those must be synchronized with the speed of the cutter with the help of the encoder

I think that you can achieve the goal, but with good hardware. Just don't economize to much. There are ready made solutions - buy them, play, learn.
There are two major control philosophies - controlling the speed or controlling the force.
As I know, Mitsubishi, ABB and Siemens have solutions that will suit you.

goghie said:

I think that you can achieve the goal, but with good hardware. Just don't economize to much. There are ready made solutions - buy them, play, learn.
There are two major control philosophies - controlling the speed or controlling the force.
As I know, Mitsubishi, ABB and Siemens have solutions that will suit you.

Click to expand...

Thanks for your reply
The machine looks like this one

https://blog.syntegon.com/wp-content/uploads/2018/01/flow-wrapper-principle.png

Today I managed to get other informations about it I'll try to explain
There's a rotary knife that has an incremental encoder atached to it
And its speed is driven by a VFD with the help of Potentiometer
So if I increase or decrease the speed of the rotary cutter I have to calculate it using the encoder and then use It to adjust the speed of the servo motor in the program ,
There are some important parameters such ase product length.
The encoder has two wires 1 gives 360ppr
And the 2nd give 1ppr and it's synchronized with the knife cut
For every knife cut the encoder gives a pulse in the second wire

And there's the eye mark sensor which I think to detect the film and to calculate the product length automatically ,and also to adjust the film position so the knife can cut the product in the desired place.The hard part for me is how can I change the speed of the servo in accordance of the speed of the knife cutter
Thanks,

LRH095 said:

Thanks for your reply
The machine looks like this one
Thanks,

Click to expand...

Another common name for such a machine is a Horizontal Flow Wrapper.

BOSCH
FUJI
etc.

Omron Sysmac Studio has a ready made FB for this type of application, Rotary Knife. You can search on Youtube, for their videos.

Their application is using servo motors / NA HMI.

Yes, Omron has it and Mitsubishi and ABB and Siemens. Mitsubishi has even complete software solution for sale (Monozukuri Converting and Monozukuri Packaging).
I think that here we have different problem. Machine is already present, PLC is either broke or there is no app backup, and LRH095 has no experience in this kind of applications.
For example I do not believe that speed is set with potentiometer that is connected to VFD of rotary knife, because rotary knife is follower and it's speed is according speed of the belt/conveyor, color mark sensor and presence of product.

goghie said:

Yes, Omron has it and Mitsubishi and ABB and Siemens. Mitsubishi has even complete software solution for sale (Monozukuri Converting and Monozukuri Packaging).
I think that here we have different problem. Machine is already present, PLC is either broke or there is no app backup, and LRH095 has no experience in this kind of applications.
For example I do not believe that speed is set with potentiometer that is connected to VFD of rotary knife, because rotary knife is follower and it's speed is according speed of the belt/conveyor, color mark sensor and presence of product.

Click to expand...

thanks for your reply,
Yes machine is already present and it has got this HMI with an integrated controller

I'm 25y old with less than 2y of experience(including internship),and this is the 1st project where I use an encoder with a servo driver.
About the speed it's actually controlled with a potentiometer that's connected to the VFD which controls the rotary knife,
and with the help of the rotary encoder I can get the frequency of the rotary knife, so from this I believe I should set the speed of the servo which pulls the film
and here's what I want to try :
I'll set the HSC input to read the frequency instead of counting with measurement of 1s
and the encoder gives me 360ppr, so if the rotary knife is cutting the product every 1s the encoder will give 360hz , if it's cutting the product every 500ms
then the encoder freq will be 720Hz,
so from this I want to adjust the speed of the servo so it'll follow the speed of the rotary knife,
any suggestions are welcome,

Look at webinar below, it is regarding rotary knife:
https://www.youtube.com/watch?v=pBe0QfkmH2s

But you will need to control web tension also, and then you will need to take in consideration color mark. For web tension it is quite complicated story.
I've seen very, very cheap solutions (4000-30000 k$), mostly from China, that do not control web tension and it is big no, no for that, because you just can't make good job without control of tension.

goghie said:

Look at webinar below, it is regarding rotary knife:
https://www.youtube.com/watch?v=pBe0QfkmH2s

But you will need to control web tension also, and then you will need to take in consideration color mark. For web tension it is quite complicated story.
I've seen very, very cheap solutions (4000-30000 k$), mostly from China, that do not control web tension and it is big no, no for that, because you just can't make good job without control of tension.

Click to expand...

Thanks for your reply.

check this solution from omron, it has 3 synchronized axes for film feeding, product feeding, and rotary knife.

https://www.omron.com.au/packaging/quality-machines.html

The Packaging Machine Library from Omron consists of three types of FBs according to the application, Rotary knife, Winder, Unwinder, PackML Support

https://www.tecnical.cat/PDF/OMRON/Sysmac_Library/W572-E1-02.pdf