EXTRUDER PURGING GUIDE

Purge extruders cleaner — cut black gels and barrel and die residue

ASACLEAN makes extrusion color changes, resin changes and built-up residue purging more systematic — with mechanical cleaning through flow, pressure and shear inside screws and flow paths

Request grade advice for extruders Calculate how much ASACLEAN to use
Film / Sheet Pelletizing Blow Molding Profile / Pipe / Tube
3D extruder showing ASACLEAN purging flow from hopper through barrel and screw to the die Flow: Hopper → Die Shear inside Barrel
Less black gel / black specks
Shorter color and material changeovers
Less resin loss at start-up
Cleans barrel, screw, die
Fits many extrusion types
HIDDEN RESIDUE MAP

Why are extruders harder to purge than injection machines?

Extruders run long flow paths with several residue-hiding spots before material reaches the die — especially the screen pack and die, whose narrow paths accumulate heat

1
Residue is not only at the die tip

Old resin can sit from hopper throat, screw channel and barrel wall all the way to the screen pack

2
Longer path than injection

Material travels barrel and adapter longer, so residue builds and releases intermittently

3
Screen packs trap residue

Screens and breaker plates can hold carbon gel until black specks appear after start-up

4
Dies are hard to purge

Narrow paths plus stored heat make residue exit slower than it looks from outside

Intermittent black gel Screen packs trap residue Flow from hopper to die
Extruder cross-section with hopper right and die left, showing hidden residue in barrel, screw, screen pack and die
1. Hopper / Feed throatOld resin can hang and flow back into the barrel
2. Screw channelScrew channels hold residue and old color along flights
3. Barrel wallBarrel walls collect heat-baked residue over dwell time
4. Screen PackHard-to-purge spots where screens trap carbon gel and black specks
5. Die lipHard-to-purge spots Narrow flow paths, slow exit before the die tip shows it

5 hidden residue spots to watch

  1. Hopper / feed throat: old resin hangs before the barrel
  2. Screw channel: residue along flights
  3. Barrel wall: heat-baked residue
  4. Screen pack: carbon gel and black speck trap
  5. Die lip: narrow path, slow hard purge
MECHANICAL PURGING

How ASACLEAN works in extruders

ASACLEAN cleans by physical mechanism — not corrosion, not chemical reaction. The point is filling the barrel with material to build pressure and shear that pull residue off walls and flow paths

Low Speed Fill

Run the screw slow so ASACLEAN packs the barrel tight

High Speed Pressure

Raise screw speed for more pressure and shear

Shear Force

Shear pulls residue off walls and paths

Residue Removal

Alternate low–high speed to carry held material out

Clean Flow

Check die discharge until it meets the cleanliness bar

10-STEP PROCEDURE

Extruder purging procedure with ASACLEAN

01
Discharge as much old resin as possible

Purge old material out of the machine first, to cut contamination

02
Clean the hopper

Stop old resin hanging and flowing back into the barrel

03
Pick the fitting ASACLEAN grade

Pick by resin, temperature, residue level and goal — e.g. color change, black-gel cut, or sealing

04
Feed ASACLEAN into the hopper

Feed enough to fill barrel and flow path

05
Start the screw at low speed

Let ASACLEAN fill the screw channels, watching motor load

06
Alternate low–high screw speed

Once flow exits the die, alternate speed for pressure and shear

07
For vented extruders

Some ASACLEAN may feed through the vent hole to clean the late barrel

08
Check die discharge

Watch the shift from old resin / black residue / mixed color to cleaner ASACLEAN

09
Feed next resin to chase ASACLEAN out

Clean the hopper, restart low, mind motor load

10
Check screen pack / breaker plate / die

Screen-mesh change jobs should follow purge immediately to cut die-hole holdup

GRADE SELECTION MATRIX

How to choose an ASACLEAN grade for extruders?

Use this table as a starting point, then verify TDS/SDS and actual machine terms before every use

Extrusion job / problemSuggested gradesWhy
General jobs / color / material changesRU, GL3Balanced cleaning power and value
Low residue / transparent / less holdupREFits as follow-up chase grade, or when residence is a worry
PE Blow MoldingUBSpecialty grade for PE and blow molding
PE Film / SheetUF2Fits film/sheet jobs needing low residue
PP ExtrusionUP, newUP, CPUP standard, newUP low-residue focus, CP budget
Black / heavy carbon / severe black gelRX, newEX, YG, CGHigh-power group — check die, screen and machine limits first
High-temp super engineering plasticsPF, PX2For high temperatures, e.g. PPS, PEEK, PEI, LCP
PC / PC-ABSPTSpecialty grade for PC and PC/ABS
Sealing before shutdownRU, GL3, RE, UP, newUP, CP, UB, UF2, PT, PFPick by resin and temperature; skip grades unfit for residence
Key note: RX (Not yet available in Thailand), NewEX, YG, CG and PX2 are the high-power group — unfit for shutdown-soak sealing. PVC jobs need case-by-case assessment, and very-high-to-very-low temperature switches should use multi-step purging

Cost Saving Calculator

Work out dosages and compare cost cuts switching to ASACLEAN

Machine and cost inputs

Suggested ASACLEAN amount
0.0 kg
Total savings per round
฿0.00

Purge cost comparison

Old method (resin purging) ฿0
Time: 0 min Wasted resin: 0 kg
With ASACLEAN ฿0
Time: 0 min Wasted resin: 0 kg

This calculator is a simulation estimate for comparison; actual results vary with machine condition

Tuning screw speed for effective purging

Good purging is not about amount alone — it is about building flow and shear inside the barrel

1

Low RPM = fill

Start slow so ASACLEAN fills the barrel, driving out air and old plastic

2

High RPM = pressure

Raise speed within safe motor load to build pressure that drives residue out

3

Pulse RPM = shear

Alternate low–high to shake residue loose, or stop–start the screw if the machine takes the load

Precautions & and maintenance (Routine… & Sealing)

❌

Never leave old resin in the hopper

It dilutes ASACLEAN and weakens the purge

⚠️

Mind motor load

ASACLEAN in the barrel can raise resistance; always start slow

🛑

Mind die holes and screen packs

Long stops let material sit or freeze in narrow paths

🔍

Never pick grade by name alone

Check resin, temperature, machine, problem and goal

☣️

PVC needs special assessment

Degradation and acid risk — consult specialists first

Routine Purging

For plants seeing periodic black gel, specks or build-up even without color changes — schedule purges to stop accumulation before big scrap

Sealing (shutdown)

For stops or production breaks — slows degradation of barrel-held resin and eases the next start-up

Applications by extrusion type

🎞️

Film / Sheet Extrusion

Main issues: black gel, die lines, specks, mixed color

Consider: UF2, UB, RU, RE, RX
💊

Pelletizing

Main issues: Residue in die holes, screen packs, breaker plates

Consider: RU, GL3, RX, YG, CG
🍼

Blow Molding Extrusion

Main issues: Mixed color, black gel, start-up waste

Consider: UB, UP, RU, RE
🪵

Profile / Pipe / Tube

Main issues: Die residue, mixed color, material changeover

Consider: RU, GL3, RE, RX
🏆

Success Story Case study: PE film plant

Old problem: Intermittent black gel in production, frequent stops, high scrap, long waits for gel to clear

Fix: ASACLEAN per the extruder procedure with low–high screw-speed alternation

Proven results:
  • Clearly less downtime
  • Less start-up resin loss
  • Black gel gone, longer runs
Want a test report like this on your machine? Contact the CSC Thailand technical team
FAQ

How much ASACLEAN does an extruder need?
Generally start from 1.5–3× the total system volume of barrel + die, adjusting to machine size and residue level
Must the die be removed before purging?
Not always — but for pelletizing, or when changing screen mesh/breaker plates, plan to open the die and keep cleaning after the purge.
Why alternate low–high screw speed?
Low speed lets ASACLEAN fill the barrel; high speed raises pressure and shear so residue releases better.
Can ASACLEAN run PE film jobs?
Yes — consider UF2, UB, RU or RE per problem and cleaning goal.
Which grade for heavy carbon?
Consider RX, NewEX, YG or CG per contamination level, budget and machine limits. (RX: Not yet available in Thailand)
Can ASACLEAN seal an extruder?
Yes — but only with sealing-compatible grades matched to resin and temperature; avoid groups unfit for in-machine residence
TECHNICAL SCREENING

Not sure which ASACLEAN grade your extruder needs?

Send resin, temperature, machine size and observed problems — CSC Thailand engineers advise fitting grades and purge methods

Send data for technician assessment

For PP extrusion jobs

Choose ASACLEAN for PP by material and cleaning goal with die and screen-pack flow-path checks on extruders

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