Blow Moulding Automatic Check-Weighing automatically improves
profitability
Bottle check weighing ¦ Drum check weighing ¦ Moog Parison check weighing
Our weighing systems send correction signal to die gap control circuits to maintain the container weight within tight limits. This process can save material by allowing you to run nearer to “bottom limit.” You will also get a more consistent performance from the blow moulding machine and other downstream equipment.
Patented process
We are the sole worldwide licensees to the Krupp-Kautex patent which covers the basic principle. We have also patented a unique method of interfacing to the machine's parison programmer.
Five ways to lose or reduce your profit margins during manufacturing
- Mould a container too heavy, you're giving away plastic.
- Make the container too light and they might get rejected by your customer.
- If the container is made too light and splits you will be charged for the clean up.
- Manufacture a container that is too heavy that is then filled to a gross weight and the company filling it can get sued for insufficient product. YOU will get back-charged.
- Bottom line, if the customer gets fed-up with YOUR problems you will lose their future business.
Why
Blow Moulding automatic weight correction?
AWC is the control process of weighing a moulding, comparing it to the desired weight and if necessary, making a correction to keep the weight within acceptable limits. It’s very similar to having a person weighing every moulding and making machine adjustments. It’s fair to assume that to achieve total repeatability of any production process none of the things that can affect the process should vary. In blow moulding this may not be possible. Variations in the incoming raw material, the variable properties of regrind, the variation in ambient temperature and humidity, and changes in the moulding machine can all conspire to cause mouldings to drift outside the desired specification.
Dual core processor
Because we designed and built our own circuit boards it was much easier for us to add sophisticated analog processing than our competitors who mostly use PLC’s. The design inertia of the large PLC manufacturers means that the chipset is often well behind current technology. With our new AQS-2 we have leapfrogged technology by using a dual core processor that makes conventional PLC based testers truly ‘yesterdays’ technology. Next time you go to buy a new laptop or desk top computer ask the salesman for last year’s model. It is no different than buying an on-line test system based on last year's PLC.
Integral or stand alone
Our Automatic-check weighing system can be supplied as an optional extra to our leak testers, or as a stand alone system. Every container is automatically weighed and compared to the limits you have set. If the actual weight is outside of your set limits the container will be rejected.
Never ship an out-of-weight container
Easy, Yes, but we can do better than that! If the container weight is heading toward the limits we give you a warning. If it's acceptable to ship over or under weight containers our check-weigher will selectively reject or pass them, or reject them into separate reject bins for quarantine. Clever? Yes - but really easy to set up !
Features - including our patented automatic die gap adjuster
- Individual and batch monitoring: Containers outside of weight limits are obviously rejected, however a warning is given if a preset number of containers fail consecutively.
- An ‘early warning setting energizes a ‘yellow alert if containers fail a less critical setting.
- Containers can be rejected into separate bins for failing high or low weight limits.
- The touch-screen display shows actual container weight, settings, average weight and standard deviation.
- The system can be interfaced to our patented “Automatic Weight Correction” feature which automatically adjusts the die gap to maintain a constant container weight.
How do we interface our Automatic Check Weighing systems to a machine's parison programmer?
Our patented technique of achieving the dynamic die gap correction is to intercept the LVDT transducer signal, process it and send it on to the machines parison programmer. This simple interface means that there is no need to go into the machine cabinet and make wiring or software changes. It can be completely disconnected in 15 seconds, and the machine functions exactly to its original configuration.
100% payback in a few months
- The system is well proven and the numerous benefits have given 100% payback in just a few months.
- Perfect for containers that have to meet tight customer specifications, UN containers, Automotive and Technical mouldings
- By ensuring optimal weight and parison profile distribution, containers will pass crucial factors such as drop and burst tests. Random samples will be as consistent as the QC ‘reference’ container.
- Eliminate the rejection of a truck load of containers if one container is found to be out of weight specification. The AWC system eliminates this problem by rejecting any containers that fall outside weight specification.
- By stabilizing the weight of the container you will be able to run nearer to ‘bottom limit’ which will of course lead to material savings.
Check weighing... is it all hot air?
Hot air balloons fly because the hot air inside them is lighter than the cold air surrounding the balloon. When a blow moulded container emerges from the machine the air is warmer inside than the ambient air outside so the whole container will ‘weigh lighter’ until the air inside the container has cooled down to the same as ambient temperature. In the case of a 220 litres ‘L’ ring drum, it can be as much as 60 grams lighter from hot to cold so if you had set the weight of the drum based on the measurement at the machine a couple of hours later the drum will be 60 grams heavier than you were expecting. Even if this overweight is acceptable to your customer, you have just given away 60 grams of material which is typically about 15 tons a year. By measuring the air temperature inside the drum and knowing the volume of the drum enables us to calculate the weight error. You are welcome to have a copy of our ‘Windows’ program ‘Mass-Calc’ to see for yourself how this works.
FAQ
Is it suitable for any blow moulding machine?
Yes, it has been fitted to continuous extrusion and accumulator head machines.
Will it work with multi-head machines?
This depends on the machine type. In some cases it will be necessary to identify the cavity number so that the correct head is adjusted. We have an optional ‘optical character recognition’ (OCR) feature capable of reading the cavity number. This was developed for the SPC feature of our leak testers. It enables the analysis of “containers rejected by cavity.” This feature can show moulders if a particular cavity on a multi-head machine is responsible for the rejection of more faulty containers which is invaluable in locating and correcting the cause of problems.
What are the ‘best’ applications? U.N. containers from 5 litres to 220 litres. have shown good weight savings, and the obvious peace of mind stemming from the knowledge that you can show proof that the containers were produced properly. Our system of storing all test results is extremely popular in countries where product liability litigation is a popular sport.
Is this system new?
No, We showed the first AWC at ‘Interplas’ about 15 years ago. This was part of our Automatic Quality System (AQS) At that time we were directly connecting our weighing system to the ‘Weight’ control of a Moog 25 point programmer. This simplified technique was a Krupp-Kautex patent of which we were their sole licensee.
Are there any problems?
Yes, it is not intended to fix a faulty machine or a faulty process. It was for this reason we declined to supply a system for a machine producing 19 litres P.C. water containers as there were shot-to-shot random weight variations of up to 50 grams. Even with our technique of analysing the trend we decided this was not a good application.