Vérificateur en ligne | How to Choose a Checkweigher | Complete Selection Guide
Choosing a checkweigher is not a matter of picking the most expensive model. It is a matter of matching eight technical factors to your product, your line speed and your compliance requirements. Get these wrong and you will have an expensive machine that cannot measure your product properly.
1. Plage de pesée
The weighing range must cover your heaviest product, and your normal production weight should sit in the lower two thirds of that range. This is the single most common selection error. A 50 g sachet running on a 1000 g machine has only five per cent of capacity on the load cell, so the accuracy figure on the data sheet is meaningless. Rule of thumb: for products below 100 g, specify a range no more than ten times your heaviest product.
2. Précision dynamique vs statique
Static accuracy is measured with a stationary load. Dynamic accuracy is measured while the product moves, and it is always worse. Ask the supplier for the dynamic figure at your actual line speed and with a product of your actual density. If they only offer a static figure, they are quoting a laboratory condition that will not occur on your line. A good supplier will ask you for product samples and test on them.
3. Résolution minimale
This is the resolution of the measurement, and for light products it matters more than accuracy. If your smallest permitted weight variation is 1 g, you need a minimum scale division of 0.1 g or better. For very light pharmaceutical products, this is the figure that matters, not the headline accuracy.
4. Largeur de bande et largeur produit
The product must sit entirely on the weighing section with no overhang, otherwise part of its weight transfers to the frame. So the belt must be wider than your widest product, with a margin. If you plan to grow pack sizes later, specify extra width now; it costs little and avoids replacing the machine later.
5. Méthode de rejet
| Air blast | fastest and cheapest, but only for very light empty pouches. Can tear thin film. |
|---|---|
| Paddle | gentle horizontal push. Best for fragile, filled or soft packs. |
| Swing arm | wide arc sweep. Suits heavier, tougher items such as cartons and cans. |
| Drop belt | product drops into a lower belt. Handles fragile product where even a push is too much. |
If your line runs more than one product type, specify at least two mechanisms and confirm they can be switched from the recipe.
6. Indice de protection et nettoyage
IP54 is adequate for dry, packaged products. If the machine is in a wash-down area, specify IP65 on the front panel and a stainless steel cabinet. The conveyor belt should be quick-release so it can be removed for cleaning without dismantling the frame.
7. Sortie de données et traçabilité
At minimum you need pass and reject counts per batch. For regulated industries you need individual weight records exportable over USB or Ethernet. Ask for the export format and confirm it can be read by your plant management or MES system. Also confirm how long the machine stores records internally, because that determines how much you can retrieve after a power failure.
8. Recettes et changement de produit
Each product needs its own recipe: target weight, tolerance, reject setting and belt direction. Lines running many formats need 200 or more recipe groups. Consider how operators create a recipe: on a good machine, following on-screen prompts is all it takes, with no engineering involvement. Quick recipe switching during changeover directly affects line efficiency.
Informations à fournir à votre fournisseur
To receive a meaningful quotation, prepare the following: the lightest and heaviest product weight, the widest pack dimensions, the product density or material, the line speed, the required accuracy and tolerance window, the reject direction, the production environment, and the data export requirement. A supplier who asks for these before quoting is a supplier who will supply the right machine.
Questions fréquentes
What is the difference between a checkweigher and a platform scale?
A platform scale measures stationary batches and is used for spot checks. A checkweigher measures every item dynamically in motion and rejects automatically, which is what modern production and most regulations require.
Is a more expensive checkweigher always more accurate?
No. Accuracy depends on the load cell, the weighing section length and the filter, not on the price. A correctly specified mid-range machine is more accurate for your product than an over-specified one used outside its range.
How many checkweighers do I need for my line?
One, if the products share a reasonable weight range and pack width. If you run 5 g sachets and 25 kg bags on the same line, you need two machines, because no single weighing range serves both accurately.