What checkweigher best fits my needs ?
Detecting the weighing / labelling system that best fits your needs is fundamental to achieve the best results and, obviously, the max profit from the investment done.
This is why it’s primarily important to clearly identify your company’s needs and to precisely define the system’s operation scenery: a careful preliminary analysis is the key for the future fulfilment!
It’s utmost important to give the manufacturer the best information possible about your requirements and your processing features: by this way your machine can be designed in the maximum adherence with your needs.
In these few lines we hope to give you some useful suggestions for this preliminary evaluation, just a little guide about what elements to consider.
1) The requested control
The first element to consider in the system’s choice is the functionality needed.
Dynamic weighing or weigh-price labeling?
It’s important to detect metal particles in the product?
Rejection of non-complying products will be manually operated or it has to be automatically performed? What is the discard reuse level?
Do you desire that packages are sorted and classified basing on measured weight?
These questions’ answer will be the starting point for the ideal machine research.
2) The product
As a tailor’s dress adheres on the body, a weighing system has to be designed basing on the products features to get the best performance.
Evaluating shape, dimensions, weight range, packaging and every other product-defining element is essential for the correct machine project.
Shape: thin based products, very tall for their footprint or round shaped are all unstable, and that will require some particular tools (for example lateral guides) to avoid they fall while running on the conveyors.
On the contrary, large based or non-rounded products are less subject to vibrations and this will not be a critical point.
Packaging: controlled products will be packed or bulk? What packaging will be used? Weighing accuracy needed for a bottled liquid product largely differs from the one required for a box components counting.
Loose products: packings like powders’ bags tend to lose some particles during the transport, with the risk of altering the scale result: this circumstance must be properly considered by the manufacturer, for example providing open-work conveyors in order to avoid leavings accumulation and periodical re-zero of the weighing program.
Liquid or viscous products: liquid, viscous or scarcely compact products (like cans of beans or paint) are subject to interior movements, due to the vibrations caused by the run on the conveyors.: these intra-packing shakes alter the results accuracy and must be considered and limited at the best during the designing phase.
Products are wet? Could they be sticky on the conveyors? The more the friction and the viscosity the more will be the weighing alterations due to the product shifting from a conveyor to another.
Weight and throughput: what’s the weight range of the product? Just a few grams or dozens of kilos? The features of the system and the required accuracy will be largely different.
What’s the speed and the spacing of the products arriving from the production line? The higher the conveyors speed the less will be the maximum possible accuracy; at the same way, it’s fundamental to have a correct spacing of the products, in order to avoid the simultaneous passage of more than one item on the scale, faking the result.
Metal contamination: the products are subject to the risk of contamination by metal particles during the manufacturing? The proper law requires metal detecting process?
Moreover, in the choice of the optimal system, it’s necessary to carefully evaluate the different products options to suit for: basing your purchase on the focus on future products possibilities allows to design a system capable of working even with products having shapes / weigh / dimensions largely different from the current range ones but, on the contrary, it often involves to choose a sub-optimal solution in terms of accuracy of weighing the current products, physical encumbrance and final cost.
3) Work environment
The environment in which the weight control system will be run directly affects the system: one of the most important tasks for a manufacturer is to evaluate this impact.
Temperature: what’s the working area temperature? It’s constant or subject to fluctuations? Repeated and considerable floating of the temperature can alter the weighing results.
Humidity and washdown: the machine will operate in a humid environment? There will be serious washdown? How the washing will be performed?
Debris and dusts: there will be volatile particles? The machine will be subject to dusts accumulation?
Vibrations: the terrain on which the machine will be posed is subject to vibrations? There will be air currents or other sources of shakes?
Corrosion: the environment will be harsh or caustic? The machine can be subject to corrosion?
The first and most important element the manufacturer has to evaluate will be the degree of the machine insulation.
This will be reflected by the machine’s IP Code, an international system that classifies the degree of protection from the infiltration of solid and liquid particles.
Moreover, the weight control system is not an independent unit, but it fits inside the production line in an organic manner. An overall knowledge of the line and the considering of the interactions and chain effects between the single elements is another key factor for the analysis performance optimization.
4) Certification
The machine has to be legal for trade or it will be just used for internal controls? A MID / OIML R-51 certification is required?
Community and international laws rule the weighing and control procedures for pre-packed goods (these are goods that are packed and weighed in absence of the customer, prepared to have a fixed weight): for these products, law complying certified systems will be mandatory.