Efficiency in a line production and the importance of accumulation in containers unscramblers
A production line efficiency depends on many factors: from the correct container unscrambling and their glide or transport to the filler until the filling and final packaging.
Each of the processes that make up a production line has its particularities. Today we would like to talk about the “accumulation” or “buffer” of the unscrambler until the filler and its importance in packaging production line efficiency.
Each of our empty container unscramblers models, either the manual change or the AAF models of automatic format change, are equipped with an exit conveyor for the containers that normally feed a filler.
It is necessary to highlight from the beginning that an unscrambler is a random machine different from the others machines that make up a packaging line, like the fillers or cappers which are continual machines where all incoming containers come out in the same position and speed.
The unscrambler is an aleatory system that does not give a regular speed and production at all times.
This difference makes that the frequency and speed with which the containers go out from the unscrambler until the filler are not the same as when the containers leave from the filler to the capper.
It is also a factor that has a direct impact on the production efficiency and must be previously evaluated in order to optimize the equipment functioning, the production performance, and minimizing the risks related to production stops.
For example, in a packaging line with 60 bottles per minute (bpm) speed, the first minute will give 65 bpm and the second will give 55 bpm.
In Traktech we always make an unscrambling production calculation of approximately 10-15% above the nominal speed of the line.
Our container unscramblers standard machines have a conveyor that excels approximately between 1,3 and 1,5 meters from the cabin. Specifically, the exit conveyor standard length is the following:
| Modelo de posicionador | Longitud ROTRAK normal | Longitud ROTRAK + OL |
| ROTRAK 1100 | 2500 | 3000 |
| ROTRAK 1300 | 2500 | 3000 |
| ROTRAK 1500 | 2500 | 3000 |
| ROTRAK 1800 | 3000 | 3000 |
| ROTRAK 2000 | 3000 | 3500 |
| ROTRAK 2300 | 3500 | 3500 |
| ROTRAK 2600 | 3500 | 4000 |
| ROTRAK 3000 | 4000 | 4500 |
That does not mean it always has those dimensions because according to the client’s layout, many times we are forced to trim or lengthen it depending on the implementation required by the client. There is always, during the offer process, several layout modifications.
How we regulate this dispersion with the speed
Even when the unscramblers and the fillers machines have different behaviors, the speed dispersion of the production line could be regulated or equilibrated by a “buffer/accumulation” between both machines.
The accumulation or buffer of the containers tries to balance the speed of the containers of the positioner and the production of the filler.
This accumulation or buffer does not take place on the exit conveyor of the machine, because the conveyor does not have a linear speed of accumulation but has an “ad hoc” speed, which means that depends on the diameter and the number of divisions that the ROTRAK model has in each case.
Therefore, we must always have the accumulation on the following conveyor. The more accumulation we have, the more regular the unscrambler will work and the more efficiency will have the line.
If this accumulation tends to 0, the line efficiency plummets because the system enters a hysteresis of start and stop point, because no matter how many divisions the unscrambler may have, it will never reach the production and will be forced to start and stop the filler and therefore all the line.
How do we size this buffer?
Obviously, it is not the same a 40 bpm production with 20mm bottles, where possible with a 400mm of buffer we could manage the accumulation, than a 40 bpm production with 200mm width bottles in which we would need 2 meters of accumulation.
Different format containers require different accumulation, hence the importance of studying each case.
As each bottle is different, inside the same machine we have a diversity of bottles and we can go from 40 bpm until 200 bpm, so each case must be particularly studied. Generally, we must have always from 1 to 2 meters minimum distance between the handover of our conveyor and the photocell (PC) minimum accumulation of the endless screw of the filler:
Our unscrambler works at a maximum speed until we achieve to cover the PC2, and there is when we go slow. Our objective is that the PC of minimum accumulation of the filler is always covered and we have the buffer/accumulation between de PC2 and the PC of the filler to make sure that the FC of the filler is never uncovered.
If that distance is “0” we would not be able to maintain always covered the PC and the filler will stop too often so the line efficiency will be decreased drastically. Hence the importance of designing a good accumulation or buffer at our unscramblers exit.
In Traktech we are specialists in rotative unscramblers for empty plastic containers with an aleatory or random system. To offer the best options to our clients we bet on studying and working together to know which are the most profitable and efficient solutions.
Do not hesitate to ask us your concerns about the unscrambling containers. We would be pleased to collaborate to find the most innovative solutions tailored to your needs. We also invite you to visit our page in LinkedIn.
