VFFS Pakaging Machine.

The answers for this are dependent on any number of factors, what type of forming collar are you using?, size of the feeder reel, how are the dancing arms set up, on and on very dependent on design.

The biggest factor is to make sure the film is allowed to pull freely from the feeder reel and have a reel braking system that works correctly.

We have found that the films we use are not the limiting factor but the delivery rate of the product to be packaged, I have seen VFFS set ups running 2900 packages a minute and have heard of rates even higher.

Are you using sterilization in line with the paper? If so this opens a whole other set of nightmares, more information is needed.

A lot of info is in your post, that is why I gave a G.A.

I have designed and operated packing lines for various clients and products and experience is your best guide.

The feeder (and or weighing/dosing) device is very important when you deal with bulk.

Bulk can be powder, liquids or units to pack. Dust and or liquids at the drop, can contaminate your seals.

Fast machines need to have a long feeder pipe to make sure that the seal has cooled down enough to ensure that the product doesn't sneak out of the bag.

Each product needs some particular approach.

A lot of information is missing here.

This is a process that is constantly tweaked by the line mechanic and the plant engineer working on the line...in short you get it to go as fast as you can, reliably...

"how much force/what max speed the PP film can be pulled without tearing it" can only be answered by the film maker or by testing each batch of film.

Think about it. Ask supplier for tear strength of film.

Then as SE said, it's your job to design the machine and make it work, not ours.

The film speed is the least of your worries. The seals are the hardest things to set up. Have a look on google for Sandyacre, Hamak and Roveama for information.

Thanks all of you for your reply.

The VFSS I have is much slower than the 10 head multi head with timing hopper. My concern is how to increase speed of VFSS by double to reach some acceptable figure. I could get about 28 packs of potato chips of 25 Gm each.

The VFSS has traction belts for film pull with a 0.5KW 3Ph motor with VFD. The multi head is not a bottle neck.

You will need to find where the bottle neck is:

Since you refer to your pulling motor - how much more speed can you introduce?

Are the belts following?

The inertia of the packing roll might be too high - perhaps you'll need to have more "cash" collector or less brake.

Your heater(s) need to be up to the task also.

Faster seals require, or more heat mass or a better temperature control (with less hysteresis)

The fastest packer for potato chips I have seen was a Bosch running at 48 packs/min.

There was already a sub- stop in the pipe as "cleaner" device for the "drop" problems.

This count also needs multiple "packer" hands to get it boxed properly. (or automation)

You're going to run in to trouble with product drop time from the weigh hopper unless you can get the machine running with the hopper release operating in advance of the bag sealing. Last one I worked on the weigh hopper was up to 2.5 cycles in advance of the seal. What type of seal head are you using, rotary or guillotine?

You need a lot more information,... How many mil thickness is your film for on thing.

Size of the package, both dimensional and weight is another.

Yes I understand many Known and unknown factors are involved.However, under given set up only variable is Motor speed other things are more or less fixed and constant.

Limiting factor for motor speed is strength of paper again a constant and belt slippage which shall increase as speed increases.

The motor is a 3Phase AC moter driven by VFD (delta make VFD007L21A).

I am doing a DOE (design of experiment) to establish best parameter (six sigma project)

I tried to change user define parameters of the FED - namely increasing frequency but motor speed remains unchanged cna any one help me on this? how to increase speed of the motor from VFD?

A PICTURE of your machine could be very helpful, because we only can have a guess what beer you're brewing.

I suggest you try with your both hands to pull down the film over the shoulder and bag forming pipe.

See if you can increase the speed easily, or if there is a lot of resistance while pulling down. (Your machine should be safe enough for this experiment- otherwise don't do it)

Coating your pipe with teflon gives less friction.

Adjusting the shoulder collar and pipe, could also give a wider bag and less friction.

To find out if the paper roll has to much inertia, cut a few meters paper off and try without the roll, leading the paper towards the shoulder. Or create a slack "cash" somewhere.

(you might need some extra hands for that)

We can give you a lot more info, but some useful feedback from you can avoid a lot of guess work done by us.

For one reason or another the applied extra pull to the motor does not affect your packing speed.

Before working on the paper, make sure that everything rolls and slides "smoothly".

Some designs require the flying "jaw" that seals the top and bottom, to pull the film downwards. (with or without belt assistance)

Timings can also be critical.

Schematic of the machine is attached.

The pair of belt pull the paper over the forming collar and tube which are made of stainless steel. They are lapped and honed for smooth finish for minimum friction. The belts drive is driven by a VFD motor.

With all these factors affecting the speed only variable is belt speed and the film strength. Again for a given film the strength is constant so is inertia of the system.

I want to increase the belt speed in increments till the belts start slipping or the film starts getting stretched to understand the limit. Then I will set back to a lower speed with a safety margin for production.

My issue is I am not able to increase the speed by increasing the frequency setting in VFD interface the trial was made by keeping the belt off the film so it was a NO LOAD condition

I am a mechanical engineer The VFD is a new subject to me. I am Looking for help in this experiment. The VFD is delta make VFD007L21A

The VFD probably has a lot of process setpoints/and/or parameters.

I used to work with a scandinavian make STEPHAN that needs a single phase connection and provides the output for up to 2kW 3 phase motors.

Starting torque, frequency, type of wave, accelleration, and much more could be preset.

Speed was adjustable with a single potentiometer of 10kOhms, connected to the board.

A VFD - 3ph/3ph could or could not have enough horns and bells to play with.

Someone who knows your make and type probably can assist you.

here is more on the net:

http://www.deltaacdrives.com/delta-vfd007l21a/

First thing I would do is check the manual or download one.

Just try Delta VFD007L21A in your browser.

As I have looked into the L- series, they are not very promising to experiment with.

Frequency -wise I read 1- 120 Hz and the power is about 100 Watts,

I would like to see something else on the machine (at least for the tests, until I get everything balanced for a certain products)

I have built machines for pretty universal type of packs. You need power and parameter controls in such case.

Good luck

With all these factors affecting the speed only variable is belt speed and the film strength.

No, the other factor is the sealing and cooling of the seal, This is what drives the speed. There has to be enough time for the heat to melt and seal the plastic,..

AND

enough time for the plastic to pass over the cooling platen. If it passes too quickly, there is a good possibility that the seal is still hot and pliable (soft) and pull apart for an improper seal.

I think Tony is closer.

25 grams Potato Chips are no big problem for 25 packs a minute. The film can be pretty thin and will heat very locally.

When the potato chips fall down, they will not open the seal, since there is no real weight pounding on there.

We did 3kg packs of chocolate mousse powder @ 16 packs a minute. That is a challenge.

Like packing with a VFFS at 2900 packs/min is a dream. I think it is a figure per hour, or a multi-line machine since for higher speeds HFFS (horizontal flow packs are used- like for candies) or cutter/wrappers (e.g. Rose Forgrove)

after reviewing Tony's post, I agree.

just leave my post on the table

I do have a question, is the product food stuff. or would require a nitrogen purge for a longer shelf life.

Potato chips:

Some use nitrogen, but in generally not.

This has to do with local requirements, the chips are supposed to be dry after the frying process.

Some manufacturer(s) even form chips from dry powder instead of slicing potatoes.

Thanks,

Some manufacturer(s) even form chips from dry powder instead of slicing potatoes.

easily formed and stackable.

And I take it your did do an analysis on the process where you were able to trim time?