HARREL HI-TECH CONTROLS FOR PLASTICS SHEET EXTRUSION LINES

HARREL, The HI-Tech Extrusion Systems People

SHEETROL^(R)II SYSTEMS FOR FULLY AUTOMATED PROFILE CONTROL OF SHEET LINES

SHEETROL II:

Closed loop control of average sheet thickness.
Automated, closed loop control of cross-machine profile.
SQC Monitoring
Total control of entire line -- Temperatures, RPM's, pressures, etc.
Stabilization of throughput to 0.1%.
Built-in compounding capability optional.

How do Harrel measurement systems work?
Harrel thickness gauges operate on a backscatter principle similar to an optical reflectometer. A narrow beam of gamma radiation is directed from the gauge head into the material. A certain portion of the energy will not pass right through but rather will be captured by the atom and cause energy to be re-radiated by the so-called Compton effect, This causes photons of energy to be returned to the head, where they are detected by a scintillation crystal, and their effect amplified by a photomultiplier tube to a detectable level. The number of photons so returned is proportional to the "basis weight" or mass per unit area of the material. Since the density is known from the initial calibration, the gauge can read sheet thickness in mils or microns.

How much experience does Harrel have?

Harrel, Incorporated has been marketing systems using nuclear gauging equipment since 1972 and we have been making our own gauge since 1978. We were the first company to develop an all-digital system using no analog circuitry in the measuring loop. We were the first to patent the use of a nuclear gauge plus an external gauge to control foam density and the first to offer "neck-in" compensation to take account of the crowding of flow lines at the edges of the sheet. We were first to combine thickness gauging with microprocessor control of the rest of the line to offer true total line control. And we were the first to offer plant-wide systems which provide total control of all lines and all machines in a plant. If you want the very best in thickness measurement and control systems -- come to Harrel!

TG-601 gamma backscatter thickness probe requires access to only one side of sheet -- a great convenience!
Uses Americium-241 -- the same isotope used in high quality smoke detectors
Half-life is 432 years! No periodic replacement of emitter required!
Can measure much thicker sections. Measurement range 1 mil to 1 inch (2 inches with reduced accuracy!)
Entirely digital -- uses photomultiplier techniques. Much more stable than beta gauges. Frequent autostandardization not required. Stability 0.25% per 24 hours!
Measurement inherently insensitive to changes in humidity, barometric pressure, smoke, etc., which can wreak havoc with beta gauges.
All Harrel nuclear gauge installations provide a radiation shield on the opposite side of the sheet -- to protect personnel from stray radiation and provide a uniform background. Resultant elimination of variations in background improves accuracy greatly.

THE HARREL "SMART TRAVERSE"

Extremely rugged, yet very precise positioning across the sheet.
Breakaway mechanism swings probe out of the way and prevents damage if a thick section comes through.
Much simpler mechanism than that required for beta gauges, since access only required to one side of sheet. No complex follower mechanism in a bottom frame required.
Off-sheet position gets probe out of the way during sheet line string-up.
Patented Harrel JACKRABBIT system speeds up overall response time enormously.
- JACKRABBIT recognizes that only portions of scan that are really of interest are those opposite the die bolt positions, for those are the only locations which can be adjusted.
- Normal linear scan wastes most of its scanning time between these die bolt positions, and even at the die bolt positions, the readings are "smeared" because the probe is in constant motion.
- JACKRABBIT traverse jumps from one die bolt position to the next at full slewing speed. Dwells at each die bolt position long enough to get a good reading and then jumps on to the next.
- Time required for a total traverse is appreciably reduced by the JACKRABBIT system.
- At selected periodic intervals a linear scan is run -- just to make sure everything is OK and there are no blockages or leakages between die bolt positions.

PRICES

Traverse Mechanism for SHEETROL II.

TM-600 Traverse with uniform traverse speed. Widths to 6 feet: $9,960
TM-601 JACKRABBIT traverse for much faster response. Width to 6 feet: $11,900.
Widths greater than 6 feet -- $200 per foot.

SC-973 SHEETROL II AUTOMATED PROFILE CONTROLLER

The SC-973 SHEETROL-II controller uses the same field-proven processor as is used in Harrel's line of extrusion system controllers. Harrel introduced the plastic industry's first microprocessor controller for control of extrusion systems back in 1975 and has improved it continually ever since.

CABINET STRUCTURES

There are three alternative cabinet structures:

Panel Mount or Table Top Cabinet
- The basic SC-973 enclosure is the panel mount unit shown above. It is 25" wide x 16" high x 18" deep. It is the same panel mounted cnclosure used in the Harrel extrusion line controllers. In fact, SHEETROL II may be combined with TOTAL line control, as described below, if desired.
- The SC-973 panel mount controller may also be furnished in an attractive 27" wide x 25" high x 19" deep table top cabinet, if desired.

6-Foot Stand-Alone Cabinet
- Attractive floor-standing cabinet mounts SC-973 controller at eye level, for convenient viewing.
- Sloping front panel keeps operating pushbuttons, switches, and pots within easy reach of operator.
- Handy shelf provides writing space for the operator.
- Lower cabinet povides space for power elements
- Recommended for upgrade systems.

Inverted "L" cabinet
- Mounted on extruder with display screen at eye level and controls within easy reach.
- Special cooling arrangement prevents overheating from extruder barrel heat.
- Particularly recommended for Harrel turnkey SHEETROL extrusion lines, where SHEETROL II is combined with TOTAL control of the entire extrusion system.
- SC-973 controller mounts in same panel cut-out as earlier Harrel controllers - the CP-671, the CP-870, CP-871, CP-873 - so earlier Harrel extruders and GEARTRUDERS may be easily upgraded to SHEETROL.

SPECIFICATIONS SC-873 Display

Full color 14" display with full graphics capability, set up for simplicity and ease-of-use.
CONTROL OF AVERAGE THICKNESS:
- As gauge is traversed across sheet, readings are taken, and the average thickness is calculated.
- Speed of roll stack is adjusted automatically to bring the average thickness of the sheet to the desired set point.
- Average sheet thickness is displayed on screen in 1" high letters readable from 15 feet away.
CLOSED LOOP CONTROL OF CROSS-MACHINE PROFILE
- Cross-Machine profile is not just indicated, it is actually controlled, using an automated die.
- 14" Full Color Display shows present status of cross-machine profile at all times.
- The display recognizes the fact that the thickness opposite each die bolt is of prime interest, for it is only here that the sheet thickness can be adjusted.
- The thickness opposite each die bolt is displayed on an easy-to-read bar chart. In-tolerance portions are in green, portions near the limits are yellow, and out-of-tolerance values are in red.
- To begin, the operator makes the rough adjustments of die bolts to bring the profile into rough conformity -- say plus or minus 5 mils. That part is easy.
- Operator then presses a button on the control panel and has a cup of coffee while the SHEETROL II control sysstem brings the cross-machine profile into tolerance. This is done completely automatically -- without the cut-and-try and "chasing the highs" of manual adjustments.
- The mechanism of cross-machine control may take either of two forms:
  - Control of profile through thermal die bolts. The temperature of the individual die bolt is changed biy means of a heated jacket encasing each die bolt of the die. When the system raises the temperature of the heated jacket, the die bolt expands, and affects the profile, just as if the bolt was turned.
  - Even better for many applications is Harrel's exclusive ULTRATHERM system. Here the sheet thickness is changed to keep the cross-machine profile constant by changing the temperature of the die lip in a controlled fashion. Raising the temperature of the lip at a given point reduces the plastic friction at that point and allows more plastic to pass. This system is ideal for relatively thin sheet or coating.
    - It is much faster than the automated die bolt system. Typical times to get on target are 8 minutes, vs. about 20 minutes for the heated die bolt system.
    - Even more important is the fact that the heaters and sensors required for the ULTRATHERM system can be retrofitted to an existing die. With the heated die bolt system, one has to start all over again.
- Both forms of SHEETROL II make use of the Harrel edge compensation system pioneered by Harrel in the 80's. This system compensates for the fact that the spacing between the sheet positions affected by adjacent die bolts is not constant across the sheet but rather is crowded at the edges of the sheet. The edge compensation system compensates for this crowding, so the display always depicts accurately the portion of the sheet affected by each die bolt (and die lip heater in the case of the ULTRATHERM system.

PRICES:

SHEETROL II System for closed loop control of average sheet thickness plus automated, closed loop control of cross-machine profile:

USING CONTROL OF THE TEMPERATURE OF THERMAL DIE BOLTS: Consists of:

TG-601 gamma backscatter thicness probe, as described above
SC-973 SHEETROL II Automated Profile Controller
- Panel mount form: $53,000.
- Mounted in attractive table mount cabinet: $55,600.00
- Mounted in attractive 6 foot stand-alone cabinet with shelf: $57,985
- Mounted in inverted "L" cabinet mounted on extruder -- Usually furnished with Harrel turnkey SHEETROL II lines.
- All forms require power module to supply power to heater: $100 per die bolt.
- All forms require traverse mechanism per listing above.

USING ULTRATHERM CONTROL OF TEMPERATURE OF DIE LIP: Consists of:

TG-601 gamma backscatter thickness probe, as described above
SC-873 SHEETROL II Automated Profile Controller
- Panel Mount form: $53,000.00
- Mounted in attractive table mount cabinet: $55,600.00
- Mounted in attractive 6 foot stand-alone cabinet with shelf: $57,985.00
- Mounted in inverted "L" cabinet mounted on extruder -- Usually furnished with Harrel turnkey SHEETROL II lines.
- All forms require power module to supply power to heater: $100 per die bolt.
- All formss require traverse mechanism per listing above.

TOTAL CONTROL OF THE REST OF THE SHEET EXTRUSION LINE

Harrel has a longer experience in the TOTAL control of the extrusion line than any other manufacturer in the business.

The Harrel DIGIPANEL controller.
- Harrel introduced the very first PID temperature controllers to the plastics industry in 1967. This made possible deep well sensing for greatly improved accuracy.
- Harrel introduced the industry's first microprocessor controller for extrusion lines in 1975.
- Harrel developed and patented the Harrel DUOSENSE^(R) control -- a barrel temperature controller using cascaded deep and shallow well sensing to combine the fast response to external conditions of a shallow well, and the fast response to process changes of the deep well.
- Harrel pioneered in the use of a melt pump built onto an extruder to stabilize the throughput to 0.1% (the Harrel GEARTRUDER^(R)).
- All temperatures are controlled. DUOSENSE deep-and-shallow well sensing optional.
- All RPM's are controlled, and roll stack speed is synchronized exactly to the melt pump or extruder screw speed with a Harrel DIGISYNCH^(R) control system -- 0.000% steady state synchronization error. This in turn stabilizes the cross sectional area of the sheet.
- Melt pressure is controlled at die, if no melt pump is used. If melt piump is employed, differential pressure across the pump is controlled to increase the stability of throughput.
- Melt temperature is controlled from an immersion type temperature sensor. (Combination pressure/temperature sensors do not indicate melt temperature accurately!)
- Full color schematic diagram of entire system. All out-of-tolerance values are in red.

Full color schemtic diagram of entire system

Trend plots -- a plot of the values of any 4 parameters of the line for the past hour.
Alarm logging -- The last 232 alarms on the system can be displayed. Includes zone number, time and date, and alarm description.
Line startup check list. Safety interlocks can be very frustrating if the operator is inexperienced. The 873 calls up a checklist of actions which must be taken before the system can be started, indicating those already done.
Speaks 4 languages. Displays in English and any of 3 other languages.
Unlimited recipe storage on 3 1/2" computer disks.
"KEEP WARM" mode drops all temperatures into standby mode.
TEL-CHECK^(R) allows Harrel factory Engineers to monitor the performance of your line from the Harrel plant. . TEL-CHECK has been a feature of Harrel extrusion control systems since 1979.
Temperature plots. The touch of a button calls up a plot of all temperatures.
Optional heater power monitoring of each heater.

PRICES:
Add overall DIGIPANEL control of the entire sheet line: $18,722.00

All temperatures:
- Up to 5 barrel zones
- Up to 4 die zones
- 2 adapter zones
- 3 chill rolls zones
- 4 melt piump and adapter zones, if SHEETROL III is present.
Command signal for extruder speed
3 command signals for chill roll speedss.
Command signal for puller roll tension and base speed
Display of all parameters of the line, with out-of-tolerance values in red.
May use exising power modules and drives, or new ones will be furnished. Consult factory for prices.

STATISTICAL QUALITY CONTROL

Harrel was the pioneer in implementing the Deming system of Statistical Quality Control for extrusion.

Histograms check that parameter follows "normal" distribution curves.
Control charts generated for any parameter -- a terrific tool for troubleshooting and process optimization.
Generates X-bar and Sigma summaries for any quality parameter. Also Cpk or any other desired quality parameter.

Print out on:
- Harrel CC-620 Plant-wide Control and Managemnt System (above)
  - Control and Management console for entire plant full of plastic machinery.
  - Full SQC data reduction, recording, and print-out
  - Total control of all parameters of any line in the plant.
  - TIME MACHINE records 30 parameters of every line in the plant for the past 7 days.
or...
- Harrel CP-603 Single Line SQC Module (left)
  - Convenient roll-around cabinet, with protected display screen.
  - Multi-copy printer for multiple copies of all quality data.
  - Full SQC monitoring, as described above.

Click here for full information, prices, and ordering directions for HARREL SQC SYSTEMS FOR SHEET EXTRUSION.

STABILIZE THROUGHPUT WITH A PRECISION
HARREL MELT PUMP AND SHEETROL III

The final step in ensuring the quality of the sheet is to stabilize the throughput of the extruder by use of a precision Harrel melt pump. Harrel was a pioneer in the application of melt pumps to the extrusion process and has been making its own precision melt pumps since 1979.

Harrel Harrel now offers a complete line of precision pumps, ranging in size from 0.014 cc/rev, up to 750 cc/rev. Special forms are aavailable for the extrusion of PVC and for fluoropolymers. You can't find a better melt pump than Harrel's!

Stabilizes throughput of system to 0.1%, vs. perhaps 5% - 10% for an extruder used alone.
Increases available output of system -- typically 15-25% or more.
Less heat stress added to polymer, since melt pump is much more efficient than extruder alone. Melt temperature at die, thus can be lower with melt pump than with extruder alone.
Can generate much higher melt pressures than extruder used alone.
Total power consumption of both extruder and melt pump is almost always less than extruder used alone. There are thus savings in power costs.
Click here for full information, prices, and ordering directions for Harrel melt pumps and SHEETROL III to stabilize the throughput.

BUILT-IN COMPOUNDING CAPABILITY WITH THE HARREL SINGLEPASS EXTRUSION SYSTEM

Whenever colorant, radio-opaque material, or other additives are required in the final sheet, it has been common practice to pre-compound the feed stock, typically using an expensive twin screw extruder. This is not only extremely costly, but also it subjects heat-sensitive polymers to two exposures to high temperature processing.

Use of a Harrel SINGLEPASS extrusion system can eliminate the extra processing step. The extruder or GEARTRUDER of the SHEETROL system is simply converted to a MIXTRUDER, using the new, patented CRD mixer developed by Dr. Chris Rauwendaal.

The CRD mixing screw gives mixing in a single screw machine that is fully equivalent to that obtained in a twin screw extruder.
The extra cost is purely nominal.
Changing from SINGLEPASS operation to normal extrusion, when no additives are to be mixed, is very simple.

Prices for adding SINGLEPASS capability:
1" extruder: $3785
1 1/4" extruder: $3785
1 1/2" extruder: $3885
2" extruder; $4706
2 1/2" extruder $5315
3 1/2" extruder $7065

To order a sheet control system on line, fill in the form below and click on "submit". Harrel will enter your order and send you an acknowledgement giving engineering data and credit requirements. Terms are 50% with order, 40% immediately prior to shipment, and 10% net, 30 days. Alternatively, you may prefer to pay by credit card (Mastercard or Visa -- number given by telephone)when the order is entered.

SHEETROL(R)II SYSTEMS FOR FULLY AUTOMATED PROFILE CONTROL OF SHEET LINES