Views: 0 Author: Site Editor Publish Time: 2026-08-28 Origin: Site
The extruder is the heart of an SPC flooring production line.
It determines how efficiently the PVC, calcium carbonate and additives are conveyed, plasticized and homogenized before entering the T-die and calendering system.
When planning a new SPC flooring factory, buyers frequently face one important question:
Should I choose a parallel twin-screw extruder or a conical twin-screw extruder?
Both technologies can be used for rigid PVC processing, and both are available in SPC flooring production equipment.
However, they are not identical.
For many conventional or lower-to-medium-output PVC applications, a properly designed conical twin-screw extruder can provide stable processing, compact equipment and effective dry-blend feeding.
For higher-output SPC flooring production, particularly when processing heavily filled PVC/CaCO3 formulations, a properly engineered parallel counter-rotating twin-screw extruder can offer important advantages in processing length, plasticization control, scalability and production capacity.
The correct decision therefore depends on:
raw material formula;
calcium carbonate loading;
target output;
flooring thickness;
machine utilization;
required production stability;
energy consumption;
screw and barrel design;
investment budget;
future expansion plans.
This guide compares the two technologies from an SPC flooring manufacturer's perspective.
There is no universal answer for every factory.
The simplified recommendation is:
production capacity is relatively moderate;
initial equipment investment needs to remain controlled;
your production formula is already proven on a conical system;
factory space is limited;
production requirements are relatively conventional.
high production capacity is required;
SPC contains a high proportion of mineral filler;
more processing length is beneficial;
stable high-output production is a priority;
energy cost per ton is an important KPI;
the factory is designed for industrial-scale or export production;
future capacity expansion is expected.
For Kingshine's high-output SPC flooring solutions, parallel twin-screw extrusion technology is used to support industrial production capacities, including high-output projects reaching approximately 2000 kg/h per line.
Factor | Conical Twin Screw | Parallel Twin Screw |
|---|---|---|
Screw geometry | Diameter decreases toward discharge | Constant screw diameter |
PVC dry-blend processing | Excellent | Excellent when correctly designed |
Low-bulk-density powder feeding | Very good | Very good with proper feeding design |
Processing length flexibility | More limited | Greater |
High-CaCO3 SPC | Suitable | Strong choice for optimized high-output systems |
High-output scalability | Good | Excellent |
Plasticization control | Good | Excellent with correct L/D and screw design |
Machine footprint | Often more compact | Often longer |
Initial investment | Often lower | Often higher |
High-volume SPC production | Suitable in certain configurations | Particularly attractive |
Screw geometry flexibility | Lower | Higher |
Future output expansion | Moderate | Strong |
Best application | Conventional PVC/SPC production | Medium-to-high-output SPC production |
This table should be treated as a general engineering guide.
Machine performance ultimately depends on the actual screw design, gearbox, motor, feeding system, formulation and supplier engineering.
SPC flooring is very different from ordinary thermoplastic sheet extrusion.
A typical SPC core contains:
PVC resin;
calcium carbonate;
stabilizers;
processing aids;
lubricants;
impact modifiers;
other formulation additives.
Unlike many conventional plastic products, SPC contains a high proportion of inorganic filler.
The material entering the extruder is normally a dry powder blend rather than conventional polymer pellets.
This creates several processing challenges.
The extruder must continuously convey a large quantity of dry blend without unstable feeding.
Calcium carbonate must be distributed throughout the PVC matrix.
PVC must be sufficiently plasticized without excessive thermal degradation.
Industrial SPC factories may require hundreds or thousands of kilograms per hour.
The extruder must supply the T-die with consistent:
pressure;
temperature;
flow;
plasticization.
Any instability upstream can appear as defects in the finished SPC board.
For these reasons, counter-rotating intermeshing twin-screw technology is widely used for rigid PVC dry-blend extrusion.
This distinction is important because many online articles use the phrase "parallel twin screw extruder" too broadly.
Twin-screw extruders can be classified according to several characteristics.
They can be:
This describes the geometry of the two screws.
They can also be:
This describes the direction in which the two screws rotate.
For rigid PVC and SPC flooring production, this article primarily compares:
Conical Counter-Rotating Twin Screw
vs
Parallel Counter-Rotating Twin Screw
This is different from the high-speed co-rotating twin-screw extruders commonly used for polymer compounding.
When requesting quotations, buyers should therefore ask the supplier to specify the complete screw configuration rather than simply saying "parallel twin screw."
A conical twin-screw extruder uses two screws whose diameters gradually decrease from the feeding end toward the discharge end.
A model may therefore be identified using two screw diameters.
The large feed section provides significant space for receiving low-bulk-density PVC powder.
As the screws become smaller toward the discharge end, the material is progressively compressed.
This geometry has made the conical twin-screw extruder widely used in rigid PVC processing.
Common applications include:
PVC pipe;
PVC profiles;
PVC boards;
WPC profiles;
SPC flooring;
other rigid PVC products.
The general process is:
PVC/CaCO3 Dry Blend
↓
Large Feed Section
↓
Material Conveying
↓
Progressive Compression
↓
Plasticization
↓
Degassing
↓
Pressure Building
↓
T-Die
The tapered geometry creates natural volume reduction along the screw.
This is one of the major characteristics of conical extruder design.
The larger feeding section provides good material intake.
This is particularly useful for low-bulk-density PVC dry blends.
The gradual reduction in screw diameter creates progressive material compression.
Conical twin-screw extruders have a long history in rigid PVC manufacturing.
Compared with some long-L/D parallel systems, the extruder can have a relatively compact footprint.
For factories that do not require very high production capacities, a conical system can be economically attractive.
A parallel twin-screw extruder uses two screws that maintain approximately the same outside diameter along their operating length.
Instead of obtaining compression primarily through tapering screw diameter, the process can be controlled through:
screw flight geometry;
channel depth;
pitch;
screw length;
processing zones;
temperature zones.
This provides engineers with greater flexibility when designing the plasticizing process.
Parallel counter-rotating twin screws are widely used for demanding rigid PVC applications, particularly when:
high output is required;
longer processing length is beneficial;
high filler content is present;
process control is critical.
Parallel systems can use relatively long L/D ratios.
This provides additional time for:
conveying;
compression;
plasticization;
mixing;
degassing;
pressure stabilization.
For heavily filled SPC formulations, this can be an important advantage.
Parallel twin-screw systems can be engineered for very high throughput.
This makes them especially attractive for industrial SPC flooring factories.
Because the screw diameter remains parallel, engineers have greater freedom to optimize different functional sections.
When properly designed, a parallel system can combine:
high output + stable plasticization + controlled processing
which is attractive for modern SPC production.
The most visible difference between the two extruders is screw geometry.
Large at the feeding side.
Smaller at the discharge side.
The geometry itself provides progressive compression.
Approximately constant diameter.
Compression and processing characteristics are created through screw design.
This affects many downstream engineering decisions:
screw L/D;
shaft design;
gearbox;
torque;
processing time;
cooling;
feeding;
output.
This is why two extruders with similar motor power can behave very differently.
SPC flooring raw material is typically prepared as dry blend.
The blend may contain a large proportion of calcium carbonate.
Stable feeding is therefore essential.
If feeding fluctuates, the entire extrusion process can become unstable.
Possible consequences include:
thickness fluctuation;
unstable melt pressure;
uneven plasticization;
changing line speed;
inconsistent board weight.
A major advantage of conical geometry is its relatively large feed section.
This can provide excellent intake of bulky PVC powder.
For many traditional rigid PVC applications, this is one reason why conical extruders became widely adopted.
Parallel systems can also provide stable positive-displacement feeding when the screw and feeding system are properly engineered.
High-output systems may additionally incorporate:
optimized screw feeding;
gravimetric feeding;
automatic material conveying;
controlled dosing.
Therefore, buyers should not judge feeding performance from screw geometry alone.
Evaluate the complete:
Mixer → Feeding System → Extruder
as one production system.
SPC cannot be judged by whether the material simply exits the die.
The material must be properly plasticized.
Poor plasticization can contribute to:
brittle board;
poor internal bonding;
unstable mechanical performance;
surface defects;
inconsistent density;
downstream processing problems.
A good extruder must provide sufficient energy and residence time to produce a homogeneous material without overheating the PVC.
This is one of the most important questions in SPC extrusion.
High calcium carbonate loading makes the formulation more demanding because the extrusion system must process a very large quantity of inorganic mineral relative to PVC.
The extruder therefore needs:
reliable powder feeding;
sufficient torque;
effective plasticization;
stable material transport;
good filler dispersion;
controlled melt temperature.
For high-output, heavily filled SPC production, a well-designed parallel counter-rotating twin-screw extruder can be especially attractive because a longer processing section provides additional time for PVC gelation and mineral incorporation.
However, this does not mean that a conical extruder cannot process high-filled SPC.
Many commercial SPC production lines use conical twin-screw extruders successfully.
The correct conclusion is:
High filler content increases the importance of screw design, L/D, torque and residence time—not simply the label "parallel" or "conical."
For a serious machinery comparison, ask each supplier to demonstrate performance using a formulation similar to yours.
L/D means:
Screw Length ÷ Screw Diameter
It is an important extrusion design parameter.
A longer effective processing length can provide more opportunity for:
material compression;
heating;
plasticization;
mixing;
venting;
pressure stabilization.
Parallel twin-screw designs are often attractive when engineers want a longer and more flexible processing section.
This can become particularly important when increasing:
filler loading;
output;
machine size.
However:
Longer does not automatically mean better.
Excessive residence time or poor screw geometry can also expose PVC to unnecessary thermal history.
The entire extrusion system must be balanced.
One reason SPC manufacturers increasingly consider parallel twin-screw technology is output.
A smaller or conventional conical line can be suitable for relatively moderate output.
As production targets increase, parallel systems become increasingly attractive.
A simplified application framework is:
Output Requirement | Extruder Direction |
Small / entry-level | Conical often practical |
Medium output | Either can work |
800–1200 kg/h class | Compare both carefully |
1500–2000 kg/h | Parallel becomes particularly attractive |
Very high output | High-performance parallel systems often preferred |
These are not universal machine limits.
Large conical extruders can also achieve substantial output.
Likewise, an incorrectly designed parallel extruder may perform worse than a good conical system.
Always compare stable actual output, not maximum advertised output.
A machinery quotation may state:
1200 kg/h
But buyers should ask:
or:
The more useful measurement is:
Stable output using the buyer's target SPC formula while maintaining acceptable board quality.
If Machine A occasionally reaches 1200 kg/h but normally operates at 900 kg/h, while Machine B continuously produces 1100 kg/h, Machine B may be commercially more valuable.
Ask suppliers about:
stable kg/h;
product thickness;
formulation;
CaCO3 content;
line speed;
board width;
actual power consumption.
Only then can capacities be fairly compared.
This question cannot be answered reliably using screw type alone.
Energy efficiency depends on:
extruder design;
motor efficiency;
gearbox;
screw geometry;
barrel heating;
cooling;
actual output;
formulation;
operating conditions.
Do not compare only:
Total Installed Power
Instead calculate:
Specific Energy Consumption = Actual kWh ÷ Tons of Saleable SPC Produced
This produces a much more useful KPI.
For example:
Machine A may have a larger motor but produce significantly more material per hour.
Its total hourly electricity consumption could be higher while its:
kWh per ton
is lower.
That is what matters for manufacturing cost.
Ask for:
main motor rated power;
total installed line power;
actual running power;
stable production output;
kWh per ton;
test formulation;
SPC board thickness.
Without these figures, "energy-saving extruder" is mainly a marketing claim.
SPC places heavy mechanical load on the extrusion system.
This is because of:
high filler loading;
material friction;
continuous industrial operation;
high output requirements.
Therefore, buyers should evaluate:
gearbox design;
allowable torque;
shaft dimensions;
bearings;
lubrication;
gearbox cooling.
A larger motor does not automatically solve mechanical limitations.
The gearbox and screw shafts must safely transmit the required torque.
This becomes particularly important in high-capacity parallel systems.
Wear is a major operating cost in SPC flooring manufacturing.
Calcium carbonate is abrasive.
As material passes through the extruder continuously, the screw and barrel experience mechanical wear.
Wear rate depends on:
filler percentage;
CaCO3 particle characteristics;
screw speed;
screw/barrel material;
surface treatment;
operating temperature;
screw design;
machine loading.
There is no reliable universal rule that one geometry always lasts longer.
Supplier marketing frequently claims large lifetime differences, but actual life depends heavily on:
metallurgy;
hardfacing;
nitriding;
bimetallic treatment;
operating conditions;
formulation.
Therefore, instead of asking:
Which screw type lasts longer?
Ask:
What material is the screw made from?
What wear-resistant treatment is used?
Which areas receive extra protection?
What is the expected life with my formulation?
How much does replacement cost?
Can the screw and barrel be rebuilt?
How quickly are spare parts available?
This produces a much more meaningful total-cost comparison.
Thickness stability is influenced by the entire extrusion line.
Important components include:
feeding system;
extruder;
T-die;
melt pressure;
calender;
temperature controller;
haul-off speed;
online thickness control.
The extruder contributes by providing stable melt flow.
If extrusion pressure or output fluctuates, maintaining board thickness becomes more difficult.
Therefore, buyers should evaluate:
pressure stability + flow stability + plasticization
rather than focusing solely on screw type.
A machine operating at low load may perform very differently when pushed toward its maximum capacity.
When evaluating a high-output SPC extruder, ask whether it can maintain:
stable amperage;
stable torque;
stable melt pressure;
stable temperature;
uniform thickness;
consistent board density.
for long production periods.
This is more important than achieving a short peak-output test.
For a factory operating 20–24 hours per day, stable long-term production directly affects:
delivery reliability;
scrap rate;
labor;
electricity;
maintenance;
profitability.
Purchase price is only one component of extruder cost.
The more important number is:
Total Cost of Ownership
This can include:
electricity;
screw replacement;
barrel replacement;
gearbox maintenance;
heaters;
temperature sensors;
oil;
seals;
bearings;
downtime;
spare parts.
A more expensive extruder may be cheaper over five years if it provides:
higher output;
lower energy per ton;
longer component life;
lower downtime.
Conical extruders are often relatively compact.
This can be attractive for smaller factories.
Parallel systems with longer processing sections may require more machine length.
However, in an SPC flooring factory, the extruder is only one part of the complete line.
You must also allocate space for:
mixers;
material storage;
T-die;
calender;
cooling;
cutting;
stacking;
UV coating;
slotting;
underlayment;
packaging.
Therefore, extruder footprint should rarely determine the entire project decision.
proven rigid PVC technology;
excellent dry-blend feeding;
progressive compression;
compact design;
suitable for many SPC production levels;
often competitive initial investment;
widely available spare parts and technical knowledge.
processing length is geometrically more constrained;
scaling to very high SPC output can become more demanding;
less geometric flexibility than some parallel screw designs;
may become less attractive for some high-output/high-filler projects.
Again, these are general tendencies rather than universal limits.
suitable for high-output SPC manufacturing;
flexible processing-zone design;
longer L/D options;
strong potential for high-filled formulations;
scalable for large factories;
suitable for continuous industrial production;
attractive for advanced automated SPC production lines.
machine can be larger;
gearbox engineering is critical;
higher-capacity equipment can require greater investment;
demands professional supplier engineering;
selecting oversized capacity can increase unused investment.
A conical extruder may make sense when:
A smaller factory may not require extremely high output.
There is no economic reason to buy very high-capacity equipment if sales do not support it.
Existing production experience can reduce commissioning risk.
Compact machinery may be useful.
A properly configured conical system can provide an effective entry into SPC production.
A parallel twin-screw extruder becomes particularly attractive when:
Large flooring factories need greater throughput.
Longer processing and optimized screw design can benefit high-filled materials.
High-output industrial factories often place greater emphasis on:
stability;
energy per ton;
durability;
automation.
Higher throughput can shorten order lead times.
A high-performance extrusion platform can provide additional capacity potential.
For this capacity level, a conical twin-screw system can be a practical option.
It can suit:
startups;
regional manufacturers;
smaller production volumes.
A parallel system may also be used depending on the machine design.
At this level, buyers should seriously compare both systems.
Evaluate:
stable output;
energy per ton;
formula;
screw life;
investment;
future demand.
Do not decide solely according to extruder terminology.
For high-output SPC flooring production, parallel twin-screw technology becomes especially attractive.
At this scale, the factory must maintain:
very high raw-material throughput;
stable plasticization;
continuous melt delivery;
balanced downstream speed.
Kingshine's high-output SPC solutions use parallel twin-screw extrusion technology for industrial applications up to approximately 2000 kg/h per line.
Another question is whether to purchase:
1 × 2000 kg/h line
or:
2 × 1000 kg/h lines
This decision goes beyond screw geometry.
Advantages may include:
fewer machines;
reduced duplication;
easier mass production;
good for long runs.
Advantages include:
higher SKU flexibility;
production redundancy;
different thicknesses can run simultaneously;
maintenance on one line does not stop all production.
This should be decided according to your order structure.
Buyers sometimes receive quotations such as:
92/188 Conical
or
130 Parallel
and try to compare them directly.
This is not enough.
A fair comparison must consider:
screw geometry;
L/D;
screw speed;
torque;
motor power;
gearbox;
screw material;
barrel material;
heating zones;
cooling;
vacuum system;
feeding;
stable output.
Screw diameter is only one specification.
Because SPC formulations are abrasive, wear resistance is important.
Ask about:
For example, alloy steel designed for extrusion applications.
Used to improve surface hardness.
Can provide additional wear resistance in critical areas.
Certain screw sections may receive additional wear-resistant treatment.
Some designs make maintenance easier by replacing high-wear parts instead of the entire assembly.
Do not simply accept:
"High-quality screw."
Ask for the actual material and treatment specification.
SPC dry blend can contain:
moisture;
trapped air;
volatile components.
During extrusion, these must be controlled.
Vacuum degassing helps reduce:
bubbles;
internal voids;
surface defects.
Both conical and parallel extrusion systems can incorporate vacuum venting.
The quality of the vacuum system should be part of the machinery comparison.
A high-performance extruder connected to an incorrectly designed die will not create a high-performance SPC line.
The T-die must match:
output;
board width;
thickness;
material flow;
melt pressure.
Poor flow distribution can create:
center-edge thickness differences;
uneven temperature;
inconsistent board weight.
Therefore:
Extruder + T-Die + Calender
should be designed as one system.
Suppose the extruder can produce:
2000 kg/h
but the calender can reliably process only:
1400 kg/h equivalent output.
Then your 2000 kg/h extruder does not create a 2000 kg/h finished-board line.
This is why Kingshine recommends evaluating complete production-line capacity rather than isolated extruder capacity.
Before choosing a machine, provide your supplier with the actual or expected formula.
Important factors include:
PVC resin grade;
CaCO3 proportion;
CaCO3 particle size;
stabilizer system;
processing aid;
lubricant system;
recycled material percentage.
Different formulations create different:
torque;
fusion behavior;
extrusion temperature;
screw wear;
output.
An extruder optimized for one formulation may not produce identical results with another.
Some SPC factories recycle production scrap back into the process.
The percentage and quality of recycled material can change processing behavior.
A professional supplier should understand:
scrap crushing;
grinding;
dosing;
formula adjustment;
feeding stability.
If recycled material is an important part of your business model, include it during equipment testing.
Before purchasing a production line, an ideal factory trial should evaluate more than whether the machine can run.
Check:
Is the kg/h stable?
What is actual consumption?
Does pressure remain stable?
Is thickness consistent?
Are there bubbles, marks or poor plasticization?
Is density consistent?
Is motor current stable?
Can the machine maintain performance over an extended run?
A five-minute demonstration is not the same as industrial validation.
Ask every supplier these questions:
Is the extruder parallel or conical?
Is it counter-rotating or co-rotating?
What is the screw L/D ratio?
What is the stable output with my SPC formula?
What calcium carbonate loading was used during testing?
What is the actual operating power?
What is the energy consumption per ton?
What is the screw and barrel material?
What wear-resistant treatment is used?
What is the recommended screw service interval?
What gearbox is used?
What is the allowable torque?
What vacuum system is included?
What is the T-die width?
What calender configuration is included?
Can the line produce my target thickness?
Can you test my raw material?
What spare parts should I purchase?
How is installation handled?
What technical support is provided after commissioning?
These questions reveal far more than simply comparing quotation prices.
Kingshine specializes in complete SPC and LVT flooring manufacturing solutions.
For modern high-output SPC flooring production, Kingshine has developed production systems based on advanced parallel twin-screw extrusion technology.
The objective is not simply to increase maximum kg/h.
The complete system is designed around:
Stable Feeding
↓
Controlled Plasticization
↓
High Throughput
↓
Stable T-Die Flow
↓
Precision Calendering
↓
Online Lamination / EIR
↓
Cooling & Cutting
The Kingshine SPC platform can be configured according to:
required output;
product thickness;
raw material formula;
factory dimensions;
downstream equipment;
automation requirements.
High-output Kingshine SPC projects include production capacities reaching approximately 2000 kg/h per line, making the parallel twin-screw system particularly suitable for manufacturers targeting industrial-scale production.
An SPC factory is an integrated production system.
The correct design should balance:
Mixer Capacity
=
Extruder Capacity
=
Calender Capacity
=
Cooling Capacity
=
Downstream Processing Capacity
If one section is too small, the entire factory becomes limited by that bottleneck.
That is why purchasing the "largest extruder" is not necessarily the best investment.
Not in every application.
Both can process SPC formulations when properly designed.
Parallel twin-screw systems can be particularly attractive for high-output and heavily filled SPC production, while conical systems remain practical for many conventional and moderate-output projects.
Both conical and parallel counter-rotating twin-screw extruders are used commercially.
The correct selection depends on production capacity, formula and machine design.
SPC uses PVC dry blend with high levels of calcium carbonate.
Twin-screw extrusion provides positive material conveying, mixing, plasticization and controlled processing suitable for rigid PVC powder formulations.
A properly designed parallel counter-rotating system can offer advantages for high-filled formulations because longer L/D configurations provide more processing time.
However, screw geometry and formulation optimization remain critical.
Yes, some large conical systems can operate at high capacities.
Output should always be confirmed according to actual formulation and finished product specifications.
For approximately 2000 kg/h industrial SPC production, a high-performance parallel twin-screw extrusion system is an attractive solution because it can be engineered for high throughput and extended processing.
Kingshine uses parallel twin-screw technology in its high-output SPC production solutions.
There is no universal answer.
Compare actual:
kWh per ton of finished SPC
under equivalent formulations and output conditions.
Screw life depends more on:
material;
coating;
hardfacing;
CaCO3;
screw speed;
machine load;
than on parallel versus conical geometry alone.
Rigid PVC/SPC sheet extrusion commonly uses counter-rotating intermeshing twin-screw technology.
Co-rotating twin screws are widely used for compounding, but the buyer should confirm the exact configuration with the equipment supplier.
Compare:
stable output;
L/D;
torque;
screw material;
barrel material;
electricity consumption;
feeding;
vacuum system;
T-die;
calender;
automation;
after-sales support.
Both technologies have a place in SPC manufacturing.
production requirements are moderate;
compact equipment is preferred;
a proven PVC dry-blend system is required;
initial investment needs to remain controlled.
output requirements are high;
high-CaCO3 formulations are being processed;
longer processing length is beneficial;
continuous industrial production is required;
production scalability is important.
For a new SPC factory, the correct decision should follow this sequence:
SPC Formula
↓
Product Specification
↓
Annual Output
↓
Required kg/h
↓
Extruder Design
↓
Downstream Capacity
↓
Energy & Maintenance Cost
↓
Total ROI
Do not choose an SPC flooring extruder because one supplier says "parallel is always better" or another says "conical is always better."
Choose the extrusion system that can demonstrate:
Stable Output + Correct Plasticization + Acceptable Energy Consumption + Long-Term Reliability
using your actual production requirements.
Planning a new SPC flooring factory or upgrading an existing extrusion line?
Send Kingshine:
required production capacity;
SPC flooring thickness;
board width;
raw material formula;
CaCO3 ratio;
daily operating hours;
target annual output;
factory dimensions;
destination country.
Kingshine can evaluate whether a parallel or other twin-screw configuration is appropriate and design a complete SPC flooring production solution around your actual manufacturing requirements.
