Overview

This procedure explains how the Station 4 dosing parameters work together to control product weight, dosing speed, tolerance, and production efficiency.

Unlike the previous Station 4 setup procedure, this adjustment focuses on the dosing parameters displayed on the HMI rather than mechanical positioning.

The main areas covered are:

1. Pre-dosing and starting weight
2. Vibrator speed during the dosing stages
3. Final weight optimization
4. Weight tolerance
5. Product particle size and its effect on tolerance
6. Reject rate versus production speed
7. Scale calibration frequency

The objective is to obtain a consistent final weight while maintaining an efficient cycle time and avoiding unnecessary rejects.

Understand the Pre-Dosing Stage

The first dosing value controls how much product enters the chute before the dosing gate opens.

In the configuration shown in the video, the initial target is approximately 0.28.

Until the product reaches this initial weight, the dosing system vibrates at approximately 1800.

Once the initial target is reached, the gate opens and the system moves to the next dosing stage.

These numbers represent the demonstrated configuration and should not automatically be used for every product or recipe.

Understand the Dosing Speed Stages

The dosing system reduces its vibration speed progressively as it approaches the final target weight.

Up to approximately 0.28 → 1800 vibration speed

After reaching approximately 0.28, the system reduces to approximately 1300 and continues dosing toward 0.46.

After approximately 0.46, the vibration speed decreases again to approximately 700 until the final target weight is reached.

This progressive reduction allows the machine to dose quickly at the beginning of the cycle and more precisely as it approaches the final weight.

Adjust for Product Overshoot

Some product may continue falling after the dosing system begins slowing or stopping.

This can cause the actual final weight to exceed the desired target.

If the machine consistently finishes above the target weight, the final dosing transition can be reduced slightly so the system begins slowing or stopping earlier.

The goal is not simply to make the programmed value equal the desired final weight. The operator must also account for product that continues moving after the dosing command changes.

Make small adjustments and observe several cycles before making another change.

Evaluate Dosing Consistency

Once the pre-dosing and final dosing values are reasonably close, observe several consecutive cycles.

The video demonstrates cycle results around 22–27 seconds, with approximately 25 seconds considered acceptable for the configuration being tested.

The system can still be fine-tuned by bringing the final weight closer to the target and reducing variation between cycles.

Adjust Tolerance for the Product

The acceptable dosing tolerance depends partly on the physical characteristics of the product.

A finer product can generally be controlled within a tighter dosing window because smaller particles allow smaller changes in weight.

A coarser product with larger particles may require a wider tolerance because each individual particle can have a greater effect on the measured weight.

For this reason, the same tolerance should not automatically be used for every product.

Understand the Effect of a Tight Tolerance

A very tight tolerance improves control over the acceptable final weight range, but it also increases the possibility of rejected doses.

If the acceptable weight window is too narrow, small variations can cause otherwise usable doses to fall outside the permitted range.

The machine will then generate more rejects, reducing overall production efficiency.

Understand the Effect of a Wide Tolerance

Increasing the tolerance creates a larger acceptable weight window.

This generally reduces the number of rejected doses and can improve production throughput.

However, making the tolerance too wide also allows greater variation between finished doses.

The operator therefore needs to find an acceptable balance between product specification, weight consistency, reject rate and production speed.

The video discusses using an appropriate positive and negative tolerance window around the target rather than setting an unnecessarily narrow range.

Optimize the Tolerance Window

Do not tighten the tolerance simply to obtain the smallest possible variation.

Instead, observe the actual dosing performance of the product.

If the machine consistently doses within a narrow range, the tolerance may be tightened while monitoring the reject rate.

If the product naturally produces larger variations because of particle size or flow characteristics, a wider tolerance may be required to maintain reasonable production efficiency.

Any final tolerance should also remain within the production requirements for the product being manufactured.

Understand Scale Calibration Frequency

The HMI includes a calibration frequency parameter for the weighing system.

In the demonstrated setup, the technician normally uses a value of approximately 15 cycles.

This means the system periodically performs its scale-related calibration routine according to that interval.

Correct a Negative Scale Reading

After removing or handling the weighing cups, the scale may occasionally display a small negative value instead of returning correctly to zero.

Change the calibration frequency to 1.

Allow the machine to run approximately 2–3 cycles.

Verify that the weight reading returns to its expected condition.

Return the calibration frequency to approximately 15.

The technician identifies this as a method he commonly uses when customers experience this type of scale reading issue.