This was more of a breakdown than a Digi Checkweigher Service but if this machine had been serviced properly the problems that caused the breakdown would of been spotted and rectified.
These Digi Checkweighers monitor the weights of product in packs such as Fried Chicken (that’s what this one was for) as the packs are travelling over the conveyor belts. It allows a continuous run of product while monitoring the average weights of the packs.
For more information on checkweighers and how they work check out this link https://en.wikipedia.org/wiki/Check_weigher
Any packs that are under or over the designated weight are rejected into a reject bin, some also have a metal detector function as well.
The conveyor belts on these weighers are driven by small brushless dc motors via a toothed drive belt.
There are rollers each end of the conveyor that turn on small bearings 636 from memory.
However these bearings are often the problem with digi checkweighers, the environment they are in is often cold and damp, any excess vibration starts to affect the effectiveness of the weigher.
Once the bearings start to deteriorate they vibrate and you then start to get weighing errors or rather alarms on the screen such as “Excessive Vibration” or “Unstable Weights” etc
So what I’m trying to say is that these rollers and bearings need paying attention to regularly and monitoring for excess vibration.
It’s quite easy to do, once they start to wear excessively you can feel the vibration through the conveyor. Ideally you would want to catch them before they get to the point of feeling/hearing the deterioration.
What I like to do is an old trick I learnt as an apprentice from an “old school mechanic” what you do is use a screwdriver as a stethoscope and place one end on the bearing housing or conveyor as close to the bearing as possible and one end in your ear.
You will be able to hear the bearing running – any grumbling will indicate the bearing starting to fail.
Yes this method is a little crude but it works, you don’t need lots of expensive equipment to find faults on equipment like this, you just need to know what you are looking for.
Often though this is not done and the bearings are left to fail causing a stoppage on the line and resulting in costing the company a loss of production for however long it takes to repair.
Another tell tale sign of imminent bearing failure is rusty dust appearing on the side of the machine around the rollers, by this point you will start to hear the “grumbling”.
These bearings/rollers don’t take too long to fit as long as you have the parts available. If the bearings have been left to fail there is a chance of causing damage to the roller itself adding to the cost.
In this case we had the parts available and we where able to replace the bearings and the seals and get the Digi Checkweigher and line up and running in under 1 hour.
However as mentioned before this breakdown didn’t need to happen.