Frequently Asked Questions

If your die is already drilled for IBC, you will need the following additional equipment:

• Cooling Blower and Exhaust Blower
• Variable Speed Drives for Cooling and Exhaust Blowers
• Cooling Coil for Cooling Blower (Optional – but highly recommended in warm and hot climates)
• IBC Die Hardware: Cooling Distribution, Exhaust Stack, Cooling and Exhaust Distribution Plenums
• Sizing Cage – Highly recommended to stablize bubble over air ring

The IBC die hardware is generally available from your die manufacturer. In some cases, other die manufacturers can build the necessary equipment for your die, but be prepared to allow them complete access to your die for internal measurements both with the die hot and cold.

In addition to supplying the IBC system, DRJ can specify blowers, cooling coils, and estimate chiller load and ducting. Properly specified blowers and cooling devices are very important to the success of your IBC project.

If your die is not drilled for IBC, it is possible in some cases to successfully drill the die. However, if complete die prints are not available, the die will have to be disassembled for this determination to be made.

If you are planning a new die purchase and have not decided on whether to drill the die for IBC or not, we recommend that all new dies be drilled for IBC. The added cost when the die is new is very low and it allows you the option to switch to IBC at a later date.

 The benefits of significantly faster startups and production rates both come from the ability to move significant amounts of air into and out of the blown film bubble.  A die designed to support IBC provides airflow passages for cold air coming into the bubble and hot air going out of the bubble.  A specially designed air distribution chamber sits on top of the die to deliver the cold air to the bubble surface.  The cold air contacts the bubble and transfers heat from the bubble to the air.  The hot air rises to the exhaust pipe, which provides the passage for the hot air to be removed from the bubble.  Two separate blowers provide the energy to move air into and out of the bubble.  A control system is required that measures the bubble size and adjusts the flow of the cooling air or the hot exhaust air in order to maintain the proper bubble size. 

The IS-IBC1 control system uses an ultrasonic non-contact sensor to sense bubble position relative to the sizing cage.  Using a non-contact sensor eliminates gauge bands that result from using mechanical arms to sense the bubble position.  When the bubble is not the same size as the cage, the system adjusts the positive pressure inside the bubble to cause it to match the size of the cage.  When the bubble is sized properly, the system continuously adjusts the positive pressure to maintain the required size of the bubble.  The system also has a fine-tuning adjustment (cage contact) that allows the operator to make very small adjustments to the bubble size.  This feature is helpful in eliminating marks caused by the cage and also in making very small layflat adjustments.

While the system is controlling the positive pressure to maintain size, approximately 300 to 3000 cubic feet of air per minute pass in and out of the bubble, which allows the film to cool more quickly and uniformly (the actual amount of air depends on the die size).  This dramatically improves production rate and quality.  It is like adding a turbocharger to your car; you will notice the difference.

The number of sensors used on the system is directly proportional to how accurate and how forgiving you want the system to be.  For instance, a system with two IBC sensors (the ones positioned nearest to the frost line) will NOT account for side to side bubble movement caused by an oscillating nip.  Ideally, if the bubble is properly blocked this issue should not occur.  But how good are your operators at blocking the bubble? 

With four sensors you get more forgiveness with this condition.  There are other similar conditions that are also operator dependent:  collapsing frame angle, sizing cage contact, and air ring stability.  Each of these issues can be improved with additional sensors.  We recommend four IBC sensors when running tubing, or other high value product where width control is particularly important.    There are other features available to help tighten layflat control even more. 

Kundig FE8 Flat width Measurement Device

Kundig Switzerland’s new FE-8 flat width measurement devices can be interfaced directly to the 3rd generation IBC and LF-Sizer systems.  This allows a confirming measurement that can be used to calibrate the IBC system, trend performance and even be used as feedback into the layflat control algorithm.  With Auto Layflat Calibration (ALC) this is done automatically, and at key points in the production process.  See the IBC System Solution Page for more info.

Automatic Cage Diameter Controller

The patented automatic cage controller allows operators to enter the desired layflat and continue with other setup issues while the system properly sizes the bubble.  The ACC maintains the proper relationship between the bubble and the cage during the size change process.  It even coordinates the size change request with the blower speeds to keep the process as smooth as possible.

NonIBC Control

With our three speed pneumatic controls, the 3GIBC1 system can also become a standard nonIBC width control system while supporting the Cage Height and Neck Height Control features.  This feature is particularly helpful for customers who are running both IBC and nonIBC dies on the same production line. 

Geomembrane Control

Running a geomembrane line requires special control algorithms that are available with the 3GIBC1 system.  New extrusion line configurations that support both Agricultural film and Geomembrane film can be produced. 

Cage Height Management System

The cage height management system allows operators to set the sizing cage to an exact and repeatable position.  This is ideal for critical application where cage height is part of the process conditions that must be maintained.  The system includes up to five configurable preset height settings plus a maintenance position that allows the cage to be moved up out of the way with a single button press, eliminating the need to hold the UP button for 5 minutes while the cage slowly moves to upper limit position.  Height information is provided relative to any reference point and is displayed in either inches or millimeters.

Neck Height Controller  (High neck – High stalk)

The IS-IBC1 has neck height control capability for high stalk, high-density bubbles.  This device measures neck position and modifies the cooling temperature of the air ring and IBC to keep the neck position stable.  The system can be interfaced with a variety of chilling/heating units.  Alternatively, the interface can be connected to the secondary input of the air ring blower, trimming air ring blower speed inversely proportional to neck position.

Bubble stability is reduced by turbulence caused by the cooling air stream when it hits the bubble. This is particularly evident for high air exchange rates.  The sizing cage offers the function of a shock absorber.  It reduces movement that the bubble would otherwise incur, and prevents the bubble from losing stability.

The sizing cage also provides the ability to artificially hold the frost line to a lower level when cage height adjustment is provided.  This benefit has been cited as the main reason for installing a sizing cage because a higher production rate is achieved on IBC and non-IBC lines alike.

New woolen, silcone, or carbon fiber roller style cages are now the preferred choice when wanting to run scratch free film.  Contact us about getting a quote on this cost effective option.

Uses of light based sensing technologies all have some dependence on the color, clarity and gauge of the film.  The more clear and thin the film, the more difficult it is for infrared, laser and camera based sensors to detect the position of the bubble.  Ultrasonic based sensing technologies have no dependency on the color or thickness of the film.  When used with a temperature compensation (internal or with another sensor), ultrasonic sensors have proven to be the most appropriate non-contact sensing devices for Internal Bubble Cooling.

Variable speed drives are an important part of good IBC control.  The key is how the variable speed drives are used.  With the significant enhancements in variable speed drive technology, it is not uncommon to question, “Why not just eliminate the flow control valve and use a variable speed blower?”  The reason variable speed blowers should not be used for bubble size control has nothing to do with the variable speed drive or the blower, and everything to do with the volume of the ducting between the blower and the blown film die.  The farther away the blower is from the die, the longer it takes to change the size of the bubble.   The delay is caused by the time it takes to first change the pressure in the ducting. The bubble size will change only after the ducting has changed pressure.  Using this type of control scheme on small bubbles or bubbles with low melt strength materials can result in poor layflat control.

The flow control valve eliminates nearly all of the delay caused by the volume of the ducting.  This is done by mounting the valve near the die (generally within 4-10 feet).  The blowers operate normally and provide a reservoir of pressure behind the valve.  The flow control valve then meters the precise amount of air into the bubble and provides a much faster response than can be provided with only a variable speed controlled blower.

The bladder valve uses parallel, expandable airfoils mounted in an arrangement that when expanded reduces the available airflow area. This reduction in airflow area decreases airflow. The advantage of this arrangement is that the pressure drop required to reduce airflow is significantly less than butterfly, shutter or rotary valves. Direction of airflow is never changed, so there is little or no turbulence caused by the valve. Because there are no flat surfaces on which the air must impinge, there is virtually no dirt buildup in the valve, which eliminates the need for periodic cleaning. There are also no mechanical linkages or adjustments.

The flow control valve is NOT installed in the exhaust for two reasons.

1. Air from the exhaust is filled with residues and corrosive gases that will affect the medium to long term performance and service life of the valve.  This means you must remove and clean the valve to prevent sluggish operation and poor width control.

2. Because the exhaust air temperature is much hotter than the supply, the density of the air is much lower.  This reduces the control effect of the flow control valve.  Because the exhaust temperature is dependent on process variables including melt temperature, material thickness and cooling temperature, it is more difficult to tune systems to provide a similar performance when the valve is mounted in the exhaust.

The system is supplied with RS232 and Ethernet interfaces.  It is also supplied with an analog signal interface for layflat and bubble position.  Available communication protocols are Modbus RTU, and Modbus ASCII, Modbus/TCP, Modbus/UDP,  Kundig PCD/2, and Kundig KRU.  Finally, with a simple protocol converter, the unit can also communicate with Profibus, DeviceNet and a host of other common protocols.

These communication capabilities make the system easily integrated with any type blown film extrusion machine and any commonly used plant data collection system.

For a sheeting producer who is able to reduce edge trim, from three inches down to one half inch, there is a potential gain of up to 1.5 production hours per 24 hour period.  In other words, on a 60 inch sheeting job that would take 24 hours with three inches of trim, if the trim were reduced to one half inch (with the exact same extruder rate) the job would finish in 22.5 hours.  This represents a 6.25 % increase in production yield.

In another example for bag producers, excessive layflat variation means giving away money.  Reducing layflat from three-quarters of an inch to one tenth of an inch can save upwards of $30,000 per year depending on resin costs.

With the industry standard Modbus protocol and the ability to handle other protocols with a protocol converter, a variety of commercial SPC tools can be adapted to evaluate the statistical performance of the system.  In addition, each 3GIBC1 and LF-Sizer system comes standard with statistics information for monitoring width control performance including: 3 Sigma width control, maximum, minimum, and average width. 

Problem solving in the blown film process is probably one of the most difficult to engage in.  Separating cause and effect is hampered by the non-linear response of the bubble.    Obviously, when a problem is occurring, a good understanding of the process is helpful.  For those that do not have that capability, D R Joseph is there to help with a multitude of service support options. 

There is also a comprehensive system manual including an installers checklist, a web based technical documentation center which includes problem solving documents, and a web based knowledge base.   You must sign up for access to our service section to access the documentation and knowledge base.  

For real time service support, each IS-IBC1 system comes with a built-in modem and Internet access port.  Either can be used to allow a DRJ certified technician to log into the system and verify proper operation and configuration.   DRJ provides 12 months free online support starting with the date of first power up.  Afterward, a variety of paid on-line support programs are available (see below).  For on-site technical support, DRJ can provide either a DRJ engineer or a DRJ certified technician to assist with problem solving.   

D. R. Joseph also has a new comprehensive paid service program (PASS) that provides for periodic monitoring, prepaid incidents, free software upgrades, discounts on parts and on site service. 

All components of the IS-IBC1 system are covered by a 12 month parts warranty and a 12 month phone support period.  The warranty period begins on the date the equipment is first powered up and it continues for 12 months or 18 months from the date the system was shipped from our factory which ever is shorter.  Extensions of the phone support period can be purchased through the PASS program.