Extrusion Following Controllers
Formulas for Setting the Counter

1. Determine the MAXIMUM extruder output in pounds per hour,
   (at 100% of full rated RPM), (max lbs/hr).

2. Determine the POUNDS per 100 of color required (lbs/100).

3. Determine the color METERING RATE; GRAMS / MIN @ display of 40;
   (gr/min@40), see below: Metering Rate.

4. Set the digital counter using the following formula:
     
   (max lbs/hr) x (lbs/100) x 3 / (gr/min@40) = Setting
     

Use this Calculator to do the math for you.  Fill in the fields in the green area then click Calculate.
Note: calculator rounds to the nearest whole number.

Metering Rate - Extrusion Following Models

METERING RATE equals the GRAMS of material metered in ONE MINUTE when the display is "40". 

To determine METERING RATE for a given material:

1. Switch the controller to the MANUAL SPEED position.
   Set the counter to "040".
   The display should also read 40. If necessary, adjust the counter up or down until the DISPLAY reads 40.
     

2. Carefully collect and weigh the output over 1 minute (60 seconds).
   This weight in grams will equal the METERING RATE for this material
   (gr/min@40)
     

Example: Your controller is running and the display shows 40. Over a 60 second period you meter 32 grams of material. Your METERING RATE for this material is 32 (grams/min@40). 

Alternate Formula Method
Extrusion Following 3 and 6 Roller Pump

This method does not require calibration, but instead relies on an accurate knowledge of the weight of the liquid (lbs./gal.) and accurate tube sizes.

1. Determine the MAXIMUM extruder output in pounds per hour,
   (at 100% of full rated RPM), (max lbs/hr).
     

2. Determine the POUNDS per 100 of color required (lbs/100).
     

3. Determine the weight of the liquid color in pounds per gallon.
     

4. Set the digital counter using the following formula:
   
    (lbs/hr) x (% let-down) x ('F' factor) / (lbs/gal) = Setting

Use this Calculator to do the math for you.  Fill in the fields in the green area then click Calculate.
Note: calculator rounds to the nearest whole number.

However, in EXTRUSION FOLLOWING controllers, we have found that better motor control and accuracy at slow speeds is obtained by always providing a full three magnets on the motor armature. Therefore, different gearbox ratios require different formulas. The formulas given above are for three different gearbox ratios using different tube sizes.

Model 6-18-G: Gearbox ratio is 101:1; speed is 18 RPMs
Models 6-34-G & 6-34-R: Gearbox ratio is 53:1; speed is 34 RPMs
Models 6-51-R & 6-51-C: Gearbox ratio is 35-1/3:1; speed is 51 RPMs

These RPM ratings are taken at 90 volts, not at full speed which occurs at full line voltage of about 130 volts.

If you are uncertain which model you have, set the counter on 200 and hold switch on 'MANUAL'. This will force the controller to run at full speed. Now count the number of turns the motor output shaft makes in one minute.

#18 motors run at about 30 RPMs, or 1 turn every two seconds
#34 motors run at 56 RPMs, or about 1 turn per second
#51 motors run at about 90 RPMs, or about 1.5 turns per second

In all cases, three magnets will produce a digital readout of about 180 at full speed regardless of the gearbox ratio of the drive motor.  If your controller only produces a full speed reading of about 120, then your unit is equipped with two magnets instead of three. If this is the case, then the "F" constants in the above formulas will be too high and should be reduced by 1/3 (or multiplied by .66).