KOR-LOK® Side Action Systems

Attention Mold and Die Builders

KOR-LOK® is the Hydraulic Locking Core Pull Cylinder recommended for all Injection Molding and Die Casting applications regardless of how the action pulls (parting line, side-action, angled, wedge, etc.). Preloading and Locking functions in the KOR-LOK are critical to success. If you are new to PFA’s products, please review the information below and/or contact PFA for our free application review and further assistance. Your success is important to us! Please call 262-250-4410.

Why Choose KOR-LOK®

More Than a Locking Cylinder:

The PFA KOR-LOK® Side-Action System sets itself apart from other Hydraulic Core Pull and Locking Cylinders by virtue of it’s ability to Preload cores to high forces. Spring locking hydraulic activated locking cylinders and other piston locking cylinders cannot achieve preload to rated load and cannot maintain that preload at zero psi. While PFA makes other locking cylinders for general industrial use, only the KOR-LOK® achieves high force preload and cylinder locking to fully rated load in a simple to install system. At PFA, we feel understanding core forces under injection, understanding the required preload necessary to overcome those force, and knowing the operation of possible solutions, is critical to choosing the correct “locking” cylinder.

Steel Compression:

Physics dictates that a pressure force applied to any material will cause compression. Without the ability to easily measure it during loading, it is often “invisible” to practical experience, leading to the false assumption that steel, for example, is incompressible and core dimensions will not change under load.

Thermal Variation:

Physics dictates that temperature changes will change the size of an object. Like compression, temperature changes are less likely to be considered and are difficult to measure. Initial reviews often assume that temperature is not an issue.

Core Changes look like “Backup”:

During injection, the resulting changes from pressure and temperature often cause the core length to decrease and the resulting core face position to be “backed up” from the desired position. These changes are “seen” on the part, as if the entire core was “backing up”, when in fact the no load room temperature timing was correct. Core face “backup” during injection may be as much as .020″ or more depending on mold geometry.

Attempting to compensate for compression and thermal effects with tryouts and “tweaking” can become time intensive, repetitive and very costly.

KOR-LOK® eliminates “core backup” by preloading the core above the force of injection.

KOR-LOK® Compensates:


Conventional "Reactive" Core Slide Positioning
An example of a conventional side-action system is to the left. A cam pin provides the means of movement and the heel block “locks” the slide in the tool. This system “reacts” to the pressure and thermal effects with the result that the core face shows “backup”.
New "Proactive" (KOR-LOK®) Core Slide Positioning
PFA’s KOR-LOK® Side-Action Systems are specifically designed to produce 10x the power of standard cylinders at end of stroke to preload the core above the injection force and then lock that force in place.
“Reactive” Method“Proactive” Method
Cam Pins, Standard Locking Cylinders, Cavity Locks, Heel Blocks, Hydraulic CylindersKOR-LOK® Side-Action Systems
In the past, core applications required choosing the best REACTIVE method available, reacting to force but not applying it. If it’s not applied force, it’s not maintaining position.KOR-LOK®’s PROACTIVE Technology™ and 100% applied force provides you with the advantages of Zero Flash™, Zero Flex™ performance.

Zero Flash Performance is Just the Beginning

We’re Saving You Time and Money Every Step of the Way

PART DESIGN – Complex parts made easy.

Core preload means your parts can be made easily with tighter tolerances, perfect match lines, and clean beautiful textures. The all-in-one system means cores can move at any angle any time, eliminating barriers to many complex parts. Specify PFA for design freedom. Indulge yourself.

MOLD DESIGN – Bolt-on actions simplify the mold.

PFA ‘s turn-key system not only makes any side-action easy, it eliminates the “one off” design and manufacture of side actions. Design it right the first time, every time with a proven system that does the job better. Technical help is available 24 hours a day and CAD files are just a click away. Design it better and faster with KOR-LOK®.

MOLD BUILD – Modular means faster and easier builds.

Simplified mold geometries, better slide performance, smaller mold bases, and independent slide movement, all mean quicker mold builds and reduced tryout time. Faster build times, fewer tryouts, and excellent part quality make your molds more competitive.

PRODUCTION – Achieve the lowest cost per part.

KOR-LOK® helps you run the best parts possible in the smallest press possible. Ensure you produce the parts you want, when you want them – reduced maintenance means improved up-time, consistent quality means less scrap, and reduced cost per part means more profit.


The Only Way to Achieve True Zero Flash Results,
Part After Part, is With KOR-LOK® Side Action Systems…


KOR-LOK® gives you:
• Perfect Match Lines• Quicker Mold Build• Consistent Part Quality
• Simplified Part Design• Lower Mold Costs• Simplified Mold Design
• Reduced Cost-Per-Part• Proven Design Performance• Smaller Mold Bases
• Unlimited Slide Travel• Greatly Reduced Wear• Unrestricted Orientation
• Reduced Spotting Time

How it Works

It Looks a Lot Like a Cylinder But it Performs Like a KOR-LOK®

(Select items from the image below to get a detailed description of individual components)

KOR-LOK® System

2D PFA Hydraulic Locking Cylinder Core Pull KOR-LOK How it moves and works

KOR-LOK® 3D View

3D PFA Hydraulic Locking Cylinder Core Pull KOR-LOK How it moves and works

KOR-LOK® Side-Action Systems provide large pre-loads and thermal compensation to core slides by use of an internal tapered locking mechanism. The threaded housing provides a base to support the locking mechanism and transfer load between the mold and the core slide, as follows:

  • SET – The rod is extended using extend pressure. As the rod nears end of stroke, the locking segments are forced into the rod groove by hydraulic pressure on the locking slide. As the segments are “squeezed,” the rod is forced forward ensuring a positive seal on the core face, while activating the sensor.
  • PULL – Retract pressure releases the locking slide, allowing the segments to disengage as the piston retracts. When fully retracted, the rear sensor is activated, indicating the slide is fully retracted.

Once set using only a minimum of 1,500 psi hydraulics, KOR-LOK® Side-Action Systems provide 100% preload to rated load – 10 times more force than a standard cylinder. KOR-LOK® doesn’t just lock, it “super locks” by preloading and locking in the force so hydraulics are no longer needed. The result is 100% preload to rated load at zero pressure.

Series SizeSet Position* Output Force
7512,000 lbs. (6 tons)
10026,000 lbs. (13 tons)
11240,000 lbs. (20 tons)
15060,000 lbs. (30 tons)
200110,000 lbs. (55 tons)
300210,000 lbs. (105 tons)

*Force ratings are at end of stroke only, based on assumed mold geometry. Ratings are for reference only. Actual performance will vary with application, setup and operating pressure.

KOR-LOK® Side-Action Systems have “User Friendly” Features

Multiple Ports – Rear ports standard

While only two hydraulic ports are used, we provide 5 SAE ports for maximum flexibility. All ports are machined in every unit. Using the two rear ports is quite popular.

Multiple sensor locations and guards standard

As sensor location may vary with adjusted preload position, multiple front and rear sensor locations are machined in every unit. Sensor guards are included to protect your investment.*

Direct Wire Relay or Proximity Sensors

Embedded dry contact sensors (XLT & XHT) verify “set” and “pull” positions without a voltage drop, making wiring multiple sensors simple and easy.** Low Profile Proximity Sensors (PNP) are also available.

Large Bore Cylinder Option

For deeply penetrating cores in high shrinkage materials, we are pleased to recommend our “LB” option. By adding a larger cylinder section to the standard fronts, pull force is greatly increased for improved core pull. Die casting materials and thermosets are typical material applications.

High Temperature Components/Metal Wipers

Flourocarbon seals (VI), Metal Wipers (MW), and High Temperature Sensors (XHT) provide the enhanced operating range for demanding environments to near 400˚F.


PFA’s new SWITCHMAX® components integrate multiple KOR-LOK® Side-Action sensors and other slide sensors into single set and pull inputs to the press with Operator side LED indication. System splitters also provide cross checking of mechanical switches to stop the press if sensors stop cycling as expected. The system can also be used with any mechanical dry contact/relay type sensors (SPDT FORM C) and with solid state sourcing style sensors, such as PFA’s PNP low profile sensor or others.

* Due to its small size, the 75 series does not have guards.
** For crash condition cores, we recommend an additional redundant sensor on the core itself to verify core retraction in the event of core to KOR-LOK® separation or false sensor reading if damaged or contaminated.

Multiple Sensor Integration with SWITCHMAX® Sensor Connectivity

Integrated SWITCHMAX connectivity available

Eliminate wiring schematics and troubleshooting problems on all molds.


PFA’s new SWITCHMAX® components integrate multiple KOR-LOK® unit sensors and other slide sensors into single set and pull inputs to the press. When used with KOR-LOK® XLT or XHT sensors and other Single Pole Double Throw (SPDT) switches, the system provides cross checking of proper sensor position, as well.


Integrate almost ANY mechanical relay/dry contact switches (plunger, rocker, PFA mechanical, relay) from multiple cores to an operator side interface for simple one input connection to the press. Full “plug and play” basic operation – NO programming or dip switching required.


SWITCHMAX® is also available in versions to integrate PFA’s new Low Profile Sensor (PNP) and other 3 wire PNP style switch sensors. For AC applications, the addition of the SWITCHMAX® AC Power Adaptor allows connection to machine controls operating with AC inputs. Power Adaptors are also available for Ø Volt Input Injection Molding machines.

Application Ideas & Recommendations

Performance Ratings

KOR-LOK® load ratings are empirically derived from a range of typical application geometries and mold behaviors. Ratings should be used only with calculations using maximum pressure and projected core area, as they already take into account some limits on preload adjustment and mold geometry, as well as cavity pressure drops, action geometry, typical core lengths, etc.

Preload ratings apply to a well secured stiff mold geometry with a core stroke of 5” or less, core lengths 5” or less, and core areas equal to or greater than core projected area. Basically, the load ratings apply to typical applications where mounting is relatively close to the part. For longer cores, or poor mounting support, it is highly recommended that the next larger unit be considered.

PFA application specialists are available to discuss recommendations, based on your particular application and their experience. While form, fit, and function for any particular application is the responsibility of the customer, following PFA recommended sizing has shown to be the best way to ensure optimal success.

Selecting Series Size

Injection pressure (P) for sizing calculations is the peak pressure at the nozzle during the injection cycle, and is a function of the injection screw piston area and ram pressure. Typical Injection nozzle pressures are approximately 10 times the hydraulic ram pressure shown on the molding machine. Easy flow plastics typically run at 800 psi hydraulic x 10 = 8,000 psi, while high temperature plastics or glass fill plastic applications may require 20,000 psi or more. Part geometries and minimum wall thickness strongly affect the required processing pressures and thus have a major impact on the series selection.

Projected core area (A) is the projected area along the axis of movement wetted by plastic, including internal shutoff areas. It may be most closely thought of as the area of a slice through the core perpendicular to the core axis. Calculation of the necessary Preload force becomes:

Minimum Preload Fore Rating (Ibs) = A (sq. in.) X P (psi).

The KOR-LOK® Side-Action System is typically chosen with a rating above this force by some margin. For a free application review please contact PFA, providing complete details, such as Core Projected Area, Core Diameter, Core Length, Stroke, Maximum Injection Pressure, Hydraulic Pressure, Material Type, and 3D Drawings of the core/mold arrangement, if possible.

Stroke to Include Adjustment

Stroke is primarily determined by the need to clear the core from the part, but practical efforts should be made to simplify overall product selection, mounting, and adjustment. Use of PFA downloadable CAD files is recommended, as CAD files provide details on the historically standard off the shelf cylinders with one to five inch strokes and relay style sensors (now – XLT), as well as, now available other strokes to 20 inches, LB bores, and the new High Temperature (-XHT) and Low Profile (-PNP) sensors, where many dimensions vary from the historically standard models.

During setup, the cylinder is advanced causing cylinder stroke to be reduced by approximately .100”. Therefore, approximately 1/8” should be added to the retract amount needed to clear the part. Also ensure the cylinder is allowed to stroke fully for proper sensor operation.

KOR-LOK Mounting Diagram

Mounting Options – Bolt C’bore & Parting Line

Use of a mounting flange (RFC/SFC), jam nut (JN), alignment screw (AS), and alignment coupler (AC) [or T-Slot in the core] is standard on nearly every application to allow for proper alignment and preload adjustment of the main unit cylinder.

mounting-diagram-2Mounting distance from the core must account for the variable E dimension for non-integer stroke units. Use of integer stroke units is recommended for ease of design and off the shelf delivery. Flanges can be mounted with counter bored mounting bolts in locations desired by the customer, as long as there is equal coverage around the KOR-LOK®.

It is recommended that bolts be located outside the diameter of the jam nut for ease of removal and that flanges be spaced off from the mold to allow KL unit to thread through the flange past the flange face approximately 1/8” (or the mold relieved to allow for preload adjustment).

If mounting the unit on the parting line, use a block to capture one side of the flange in place of the mounting bolts. Call PFA for mounting ideas and information regarding proper mold sequencing for flange capture applications.

High Temperature Seals, Wipers, and Sensor Options

Front (set-locked-preloaded) and rear (pull) sensors (switches) and cables are included with each
KOR-LOK® main unit. Use of the sensors during setup and adjustment assists in verification of proper operation (see pages 14-15). The SWITCHMAX® junction box and cabling is recommended for multiple core applications, crash condition cores, or when cross checking of sensor positions or LED indication is desirable.

High Temperature Seals (VI), Metal Rod Wiper (MW) and High Temperature Relay Sensor (XHT) options are available for very high temperature plastic and die casting environments. For some applications, insulation between the flange and the mold (or flange cooling) may be needed.

Driving Wedges and Racks

Because the KOR-LOK® generates preload though an internal wedge style force intensifier, wedge applications and rack and pinion designs often limit the ability for the main unit to preload the core face.

For wedge applications, preloading the prime mover is often enough to hold the core in position for successful part production, however the core face itself is often not substantially preloaded. As these applications are often difficult in concept, use of the KOR-LOK® system can provide substantial advantages, however, we recommend careful PFA staff review.

Rack and Pinion applications typically have special challenges with a large preload force applied to the gear teeth. Typically the racks are not sized large enough to handle the forces needed to transmit the preload to the core. Careful review is recommended to determine feasibility.

PFA Application Review

Making the difficult easy and successful is one of the great advantages of the KOR-LOK® Side-Action System and we are proud to back that up with the best in service and support. For best results, please have a PFA application specialist review your selection criteria to help ensure nothing was missed. When it looks like a challenge, our application specialists are on your side to find a way to make the difficult easier. For the most detailed sizing information, product specifications, design suggestions, CAD files, and new product updates, call your application specialist or visit us at www.pfa-inc.com.

All PFA KOR-LOK®, DIE-LOK™ and Switchmax® application and use recommendations are advisory only. KL/DL preload force ratings are geometry dependent and based on PFA recommended sizing methods. Process variations may affect actual performance. PFA recommends use of PFA’s Switchmax® cross connected sensor checking and independent 2nd pull sensor (redundant) “core pulled” sensing on molds where opening with cores set could damage the mold. False readings in the event of single sensor failure, cylinder contamination, core to cylinder separation, attachment failure, etc. may occur. PFA is not responsible for situations arising from false sensor readings, product failure, misuse, or abuse – proper form, fit and function are the responsibility of the customer. PFA “Terms of Sale” apply.

These procedures have been written in an effort to address as many configurations as possible. If your particular application requires set up procedures that are not covered in the preceding documentation, please contact PFA at (262) 250-4410 for assistance.

Dimensional Information

(All dimensions nominal and in inches)

  • Calculate Preload:  Core Area x Max Injection Pressure = Force
    Select Output Intensifier Force (Preload) > Force
  • Adjust chosen stroke for Preload:  Add .125” to stroke needed to clear part.  Cylinder Stroke = Stroke to Clear + .125”
  • Part Penetration and Shrink:  Choose LB (Large Bore) option for extra pull as needed.
  • Seal Selection:  Choose High Temperature Seals VI  if slide/mold exceeds 175˚F/80˚C.
  • Sensor Selection Options:  Relay Low Temp XLT, Relay High Temp XHT, Low Profile PNP.
  • High Temperature Sensors:  Consider XHT option if temperature exceeds 175˚F/80˚C.
  • Rotational Adjustment Clearance:  Consider Low Profile  PNP sensors with SWITCHMAX® for an easy alternative to XLT sensors.
  • Multiple Cores/Slides:  Consider SWITCHMAX® connectivity solution for single press input (easy interface) of set and pull.
  • Crash Condition Cores:  Consider -XLT or -XHT with SWITCHMAX® (cross check sensors) – sensor on core recommended.


Main Unit (KLH-_______-(stroke) – Options)
Series SizeOutput Intensifier Force***(Preload)Min. Pressure for Full PreloadPressure to Maintain PreloadBore Dia.Rod Dia.Extend Force @1500psiRetract Force @1500psiAME**RVIC**
7512,000 lbs.1,500 psi0 psi1.25”0.75”1,825 lbs1,125 lbf2¾”-160.75”0.50”2.25”⅜”-246.22”
10026,000 lbs.1,500 psi0 psi1.75”1.00”3,600 lbs2,425 lbf3½”-161.00”0.50”2.75”½”-207.26”
11240,000 lbs.1,500 psi0 psi1.75”1.125”3,600 lbs2,100 lbf3½”-161.00”0.50”2.75”⅝”-187.26”
112-LB*40,000 lbs.1,500 psi0 psi3.00”1.125”10,600 lbs9,100 lbf3½”-161.00”0.50”2.75”5.14”⅝”-188.59”
15060,000 lbs.1,500 psi0 psi2.00”1.50”4,700 lbs2,050 lbf4”-161.25”0.75”3.38”⅞”-168.93”
150-LB*60,000 lbs.1,500 psi0 psi4.00”1.50”18,800 lbs16,175 lbf4”-161.25”0.75”3.38”7.04”⅞”-1610.75”
200110,000 lbs.1,500 psi0 psi3.00”2.00”10,600 lbs5,850 lbf5”-121.75”1.00”3.75”1¼”-129.98”
200-LB*110,000 lbs.1,500 psi0 psi5.50”2.00”35,600 lbs30,900 lbf5”-121.75”1.00”3.75”8.03”1¼”-1212.49”
300210,000 lbs.1,500 psi0 psi4.00”3.00”18,800 lbs8,225 lbf6¾”-82.00”1.25”5.00”1¾”-1212.08”
Outer Dimensions, Ports and Sensor Options
Series SizeOutput Intensifier Force*** (Preload)Body Dia.Nn(SAE)PNP Low Profile ProxOriginal XLT Relay Low TempXHT Relay High Temp
7512,000 lbs.3.00#44.8”4.0”0.5”7.8”7.1”1.9”9.3”7.9”2.7”
10026,000 lbs.4.00#45.6”5.1”0.6”8.4”7.7”2.1”9.9”9.2”2.9”
11240,000 lbs.4.00#45.6”5.1”0.6”8.4”7.7”2.1”9.9”9.2”2.9”
112-LB*40,000 lbs.4.006.00#4#65.6”6.9”0.9”8.4”8.9”2.3”9.9”10.4”3.1”
15060,000 lbs.4.50#66.1”5.3”0.9”8.9”7.9”2.3”10.4”9.4”3.1”
150-LB*60,000 lbs.4.507.50#6#86.1”8.1”0.9”8.9”10.1”2.3”10.4”11.6”3.1”
200110,000 lbs.6.00#67.0”6.9”0.9”9.9”8.9”2.3”11.4”10.4”3.1”
200-LB*110,000 lbs.6.009.00#6#87.0”9.5”0.9”9.9”11.5”2.3”11.4”13.0”3.1”
300210,000 lbs.7.50#88.4”8.1”0.9”11.3”10.1”2.3”12.8”11.6”3.1”

*LB Option – Large Bore units have all the same accessories as standard units.  Use -LB in the main unit order code only.

** Use of PFA downloadable CAD files is recommended, as CAD files provide details on the historically standard off the shelf cylinders with 1”-5” strokes and relay style sensors (now – XLT), as well as other stroke units, LB bores, and the new High Temperature (-XHT) and Low Profile (-PNP) sensors, where many dimensions vary from the historically standard models. 75 series has no guards. Guard chart dimensions O and P show swing arc clearance diameter during adjustment. Alternate front sensor location included in the event that interference occurs at final adjustment position.  Q is for alternate rear sensor position, if used in place of the rear side location.

***Output Mechanical Intensifier Ratings are for end of stroke (general reference only).  Actual performance is dependent upon application geometry, setup and adjustment.  Mid stroke and pull forces are less.  Minimum operating pressure is 1,500psi to set with full rated preload.  After locking, preload is maintained with 0 psi, hydraulics are NOT required to maintain lock.

PFA KOR-LOK Locking Cylinder Accessories - dimensions
Jam Nut [KL-______-JN]     Alignment Coupler [KL-_______-AC]     Alignment Screw [KL-_______-AS]
Series SizeT/tB/bSsIZ (set)Z (pull)J**gGHef/k
753/8”-240.57”.56”1.00”1.13”0.91”0.93”0.690”2 3/4”-163.50”0.50”0.31”0.13”
1001/2”-200.75”0.81”1.25”1.375”1.10”1.13”0.785”3 1/2”-164.50”0.63”0.31”0.13”
1125/8”-180.79”0.88”1.31”1.46”1.12”1.14”0.785”3 1/2”-164.50”0.63”0.31”0.13”
2001 1/4”-121.38”1.50”2.75”3.00”2.90”2.92”2.125”5”-126.50”0.88”0.50”0.25”
3001 3/4”-121.58”2.13”3.37”3.63”4.16”4.18”2.995”6 3/4”-8”8.75”1.00”0.63”0.31”
Flange (Round or Square) [KL-_______-RFC or -SFC]
Recommended Bolt Circle with C’Bore SHCS

Series SizedD*F*Recommended Bolt Size/QuantityC'Bore bolt CircleDepthDia.Bolt Circle No C’Bore
752 3/4”-166.0”1.00”1/2” x 63.75”-5.00”.56”.81”4.5 Ø-5.25”
1003 1/2”-167.2”1.50”5/8” x 64.75”-6.00”.69”1.00”5.75”-6.25”
1123 1/2”-167.2”1.50”5/8” x 64.75”-6.00”.69”1.00”5.75”-6.25”
1504”-168.0”1.50”5/8” x 65.25”-6.75”.69”1.00”6.50”-7.00”
2005”-1210.0”2.00”3/4” x 66.50”-8.50”.81”1.19”8.00”-8.75”
3006 3/4”-814.0”2.50”1” x 128.75”-12.251.06”1.56”10.50”-12.50”
Wrench [KL-_______-SWJ]

*Flanges have no pre-drilled bolt holes for maximum design flexibility. Grade 8 bolts recommended. Since flange edges are flame cut and faces are machined flat, allow +.200/-.000” for edges and +.000/-.300” for faces (pilot off center thread only).

**Alignment screw has a convex face to promote proper centering of the axial load, and is designed to create a loose fit, with the mating coupler or appropriately designed T-Slot, to help accommodate misalignment.

PFA SWITCHMAX LED cable system drawing layout for PNP or mechanical sensors
KOR-LOK Main Locking Cylinder Part number specification
KOR-LOK Accessories for Locking Cylinder Part number specification
PFA SWITCHMAX LED cable system part number specification

Main unit and mounting accessory example for a large bore 150 series. Note that LB is only used for the main unit as 150-LB and 150 units have common accessories:

QuantityPart Number
1KLH-150-LB-XLT-3.00Main Unit
1KL-150-SFCSquare Flange
1KL-150-JNJam Nut
1KL-150-ASAlignment Screw
1KL-150-ACAlignment Coupler
1KL-150-SWJSpanner Wrench
1SM-KL-DCPKG-1SSwitchmax® Wiring
PFA SWITCHMAX Relay Sensor and system test box

To test sensors of complete installations a Switchmax® test box is available. Part No. SM-RTB-1A

part-solutionsClick here for CAD MODELS by PARTsolutions.  CAD Models are available in over 150 native and neutral CAD and graphic formats, versions and revisions. That means no matter what system your using, you can download KOR-LOK Models in your native format, which can be easily imported with all geometric integrity and meta data intact.

“No other catalog provider offers as many CAD and graphic formats as PARTsolutions. Guaranteed.”

– Rob Zesch, President CADENAS PARTsolutions

Download CAD Files

PFA provides FREE APPLICATION REVIEW SUPPORT and parametric 3D CAD models in partnership with CANENAS Part Solutions.  Please review the below recommendations and download your CAD file.

NOTE:  All “free-mail” domains such as gmail, yahoo, Hotmail, etc. are blocked and cannot be used to receive downloads.  Please use a corporate email account when logging into the CANENAS Part Solutions configurator.

FREE Application Review Support

Our Applications Specialists have reviewed literally thousands of applications. Let our experience work for you! Please contact us early in the design process to discuss recommended options or Email your concept/preliminary layout files to us and we will be happy to share our experience.  We can open 2D and 3D files in a wide variety of formats. Typically we will not have a problem opening whatever you send, so please email it.

We will provide our recommendations for size, orientation, shutoffs, stops, etc., and point out any possible limitations of the proposed design affecting proper core preloading.  As consulted experts in retrofit and new core applications, we pride ourselves as a resource to those of you in search of zero flash performance.  While customers that follow our recommendations typically produce highly successful molds, it is our goal to train and provide guidance so that you can make the decision on product selection and cover all the parameters important to your design.  Our sizing and review ideas tend to be conservative and based on our experience.  See Applications/Sizing for ideas on how we calculate forces and unique mounting configurations.

3D Model and 2D CAD Downloads

Parametric 3D Models and 2D CAD Files are available in about 100 native formats, by partnering with CADENAS Part Solutions.  The download file of the KOR-LOK (preloading locking cylinder) will also include chosen accessories.  In the table below is a menu on the left and image pane for the model on the right.    For a better understanding of dimensions, See the Dimensional Information on our website –  dimension information section.  For additional information on selecting CAD file options, help for specific CAD systems, or more details on how to use the configurator, please see instruction below.

Selecting Product Part Number and Accessories Information – After reviewing the PFA sizing methods and recommendations, select all the options for the KOR-LOK desired and accessories needed:

  • Series Size – this is the model size.
  • Large Bore Option – select if large pull force is desired.
  • Stroke – Available in 1/100 th inch increments (example 2.75, 1.13, etc)
  • Stroke Position – provides the model with the rod extended or retracted.
  • Sensor Style – see Sensor information page for details.
  • Metal Wiper Option – Typically for Die Casting
  • High Temp Seals Option – For applications where the mounting or core interface would exceed 200 F
  • Accessories Alignment Screw – Select if Male rod end coupling is desired (recommended)
  • Accessories Alignment Coupler – This is the female (T-Slot) piece for the rod end – Use if T slot not in core.
  • Accessories Flanges – Choose either the Round Flange (RFC) or Square Flange (SFC). Both allow c’Bore of Bolts.
  • Accessories Jam Nut – Choose this as all applications need the Jam Nut.
  • Accessories Spanner Wrench – Used to tighten and loosen Jam Nut (recommended).
  • Front Sensor Location – Standard is in line with the rear side sensor. Alternate is 180 degrees.  (sensors are always included).
  • Rear Sensor Location – Standard is out the side of the rear head.  Alternate is out the back of the rear head.
    Please note that all 4 sensor ports (2 front/lock and 2 rear/pull) are included and all 5 hydraulic ports (set – 2 ports and pull – 3 ports) are included with unused ports plugged for future use, if needed.  Selection in the CAD file creator simply provides a location for the model and does not affect the part number ordered.  Please review the product pages or contact PFA for details.

View 3D model/Preview – Generally the part will render in 3D or select “Update Preview” in the image area.  The model will be created and can be rotated by clicking and holding while moving the mouse as is typical in many CAD systems.  The small menu on the upper left and various action buttons on the bottom can be used to gain various impressions of the model and some dimensions. Selection of various options and accessories can be done and new models generated.  Selecting the Dimensions Tab in the image window will bring up 2D layouts.  The letters on the drawings reference dimensions shown on the left below the selectable options.

CAD file downloads – Click on the CAD Download Tab in the image area and follow the prompts….. Enter your email address and “Accept” the license agreement.  Select the CAD download image.  Select the file type desired and click on the Start Download button.  If you have not been on the system before, a Data window will appear to enter your Name and Company information.  Click “OK”.  Please allow time for the file to generate and then choose Download at the right.  The CAD file should download to your system.

Help – Most creations are simple and downloads easy to get, however for those interested in advanced features or for those using CATIA (CATIA Support) and SolidWorks (SolidWorks Support), viewing the help files is recommended to ensure smooth and successful results.  Configurator Help reviews items that affect the ability to operate the online viewer and what file types are available.  Typically customers have a smooth experience, however, the configurator does require JAVA and some graphics software that may not come preloaded in generic browsers.  Different browsers such as Chrome, may require the installation of plug ins. Please try these recommended solutions. For additional help or other information go to CADENAS Part Solutions (Main Support Page) or call PFA for assistance.

Installation / Maintenance

Read the following instructions carefully, paying close attention to the sections that pertain to the model you have purchased. If you have any questions or need technical assistance, please call our support staff at (262) 250-4410.

Installation Video

Preload Adjustment Video

Installation Guide

Adjustment Procedure for Currently Installed Unit
  1. Retract cylinder and loosen Jam Nut.
  2. Unscrew cylinder from flange a few turns (counter-clockwise) – allows slide to travel fully without touching stops or shutoff.
  3. Connect hydraulics and power the cylinder forward to the extended/locked position – core should not seal off or hit stops at this time.
  4. Critical Step!!! Disconnect hydraulics and VENT the cylinder to atmosphere by removing one (1) extend and one (1) retract port plug.
  5. Thread the cylinder into the flange (clockwise), until the core seats and the cylinder physically stops turning. Note: you should not be able to turn the cylinder any further by hand – it should be solidly stopped.
  6. Reinstall the port plugs, reconnect the hydraulics, and retract the cylinder.
  7. Critical Step!!! Rotate the cylinder further into the flange (clockwise) the additional amount shown on the chart below to set the preload:
    751/6 turn
    1001/6 turn
    1121/6 turn
    1501/3 turn
    2001/4 turn
    3001/8 turn
  8. Tighten the Jam Nut.
  9. Setup is now complete. Unit will make good parts for most applications. If more output force is required (core is flashing slightly), rotate the cylinder into the flange further (clockwise) in small increments (approximately 1/16 turn) until the flash goes away.
Procedure for Installing a New Unit
Tips regarding accessories
  • ALIGNMENT SCREW (AS) AND COUPLER (AC): If you require Alignment Screws and/or Couplers install these first. Install the Alignment Coupler (T slot) in the core and the Alignment Screw (knob) into the piston rod until fully seated. A thread locking compound may be utilized if desired.
  • MOUNTING FLANGES (SFC or RFC): The Mounting Flange is provided without pre-drilled mounting holes. (See recommendations) Ensure threaded hole is centered relative to the core attachment point and torque flange bolts to appropriate specifications.
  • JAM NUT (JN): Install the Jam Nut onto the KOR-LOK® unit with the beveled edge toward mold. Thread the Jam Nut most of the way on.
  • Spanner Wrench (SWJ): A wrench can be purchased for easier tightening and loosening of the Jam Nut. Many customers use a brass rod and hammer, but this method typically causes damage to the Jam Nut slots over time.
Preparation for Installation of the Main Unit – On the Bench
  1. Remove port plugs from one extend and retract port. There are three options for the retract port (A, B and C) and two options for the extend port (D and E) as shown in Figure 1.
    CAUTION! Fluid may eject from retract port as rod extends. Observe proper safety precautions.
  2. Apply a pressure source (minimum of 80 psi pneumatic or hydraulic) to the open extend port (D or E) until the unit is fully extended/locked.
Installation of Main Unit
  1. With the unit extended/locked, and vented (port plugs removed on one (1) extend and one (1) retract port), connect the core slide to the rod and thread unit into the flange a few turns.
    NOTE: For long term ease of adjustment, application of anti-seize or other thread lubricant may be desired.
  2. Thread unit inward (clockwise) until the core is fully seated and cannot be turned in by hand – solidly stopped.
  3. Ensure proper thread engagement of the cylinder and flange – equivalent to the thickness of the flange.
  4. Ensure that there is space beyond flange for unit to thread through for adjustment. See required flange thickness for your model size (refer to “Recommended Accessories” section of catalog).
  5. Place mark on flange and unit body to mark position location for reference.
  6. Reinstall the port plugs, reconnect the hydraulics, and retract the cylinder.
  7. Thread the unit Inward (clockwise) the recommended pre-load amount in the chart below.
    751/6 turn
    1001/6 turn
    1121/6 turn
    1501/3 turn
    2001/4 turn
    3001/8 turn
  8. Tighten Jam Nut.
  9. Connect sensors using appropriate procedures for the style utilized in your application. Documentation is provided separately.
  10. Extend unit HYDRAULICALLY (1500 psi minimum) and verify lock sensor activates (turns on) ensuring unit locks as expected. Failure to lock is one indication of an adjustment problem.
  11. After extending and locking, the preload stretches the large threads which may cause loosening of the Jam Nut. Re-tighten the jam nut, if desired.
    (Note: If the jam nut is tightened while the unit is preloaded, future loosening of the jam nut will require extending and preloading the unit).
  12. Cycle unit hydraulically several times and verify complete operation.
  13. Test Mold during injection and note part quality.
    If flash occurs, additional preload adjustments (1/16 turn increments clockwise) may be needed at normal operating temperature to achieve the desired final adjustment. If unit does not operate as intended, call PFA for assistance. Applications vary widely and this procedure may not exactly cover all geometries. 24/7 technical phone assistance is generally available.

XLT and XHT PFA Dry Contact/Relay Sensor Wiring Instructions

Standard EE 70194/CT70300 (assembly) and High Temperature EE70199/CT705XX (Assemblies)

Fig. 1 - Single Sensor Wiring

Fig. 1 – Single Sensor Wiring


Fig. 2 - Multiple Sensor Wiring (Series)

Fig. 2 – Multiple Sensor Wiring (Series)

PFA Relay-style sensors (CT70300 assembly CT70520/21/22… High Temperature Assembly) function as a true dry contact switch. In normal usage, when the target comes “in range” of the sensor, the magnet inside the switch closes a contact to complete the circuit.

CT70300 Assembly Specifications
Part No. on Sensor:EE70194
Cylinder Designation:-XLT
Contact Type:SPDT (Single-Pole, Double Throw)
Contact Rating:2 Amps @ 12OVAC
1 Amp @ 240VAC
1 Amp @ 24VDC
Temperature:-40˚F (-40˚C) to 257˚F (125˚C)
Pressure:3000 psi max.
Install Torque Max.:50 in-lbs. max.
CT70520/21/22…Assembly Specifications
Part No. on Sensor:72-16222-F4
Cylinder Designation:-XHT
Contact Type:SPDT (Single-Pole, Double Throw)
Contact Rating:4 Amps @ 12OVAC
2 Amp @ 240VAC
3 Amp @ 24VDC
Temperature:-40˚F (-40˚C) to 400˚F (204˚C)
Pressure:3000 psi max.
Install Torque Max.:50 in-lbs. max.

Relay-style switches offer many benefits to the user. They have no voltage drop when closed nor do they have leakage current when open. In most applications the Normally Open (N/O) connection is used so that when the cores reach set or pull, the relay contacts close to give that indication to the press. In most cases, the Normally Closed (N/C) connection is not used, but is available for use as part of PFA’s SWITCHMAX® Mold Wiring solution.

Connection between the KOR-LOK® Side-Action System and the press, is as simple as connecting two set sensor wires and two pull sensor wires to the two pair of machine control wires. The order of connection for each pair is not important.


Multiple set sensors may be wired in series to provide a single set indication to the press. Similarly, the pull wires may be connected in series. For situations where a core or other part of the mold may be damaged if opened with cores set, it is recommended that a redundant sensor be placed on the core itself and wired in series with the main unit sensors to ensure the core is retracted prior to mold opening.

PFA’s SWITCHMAX® Mold Wiring solution is also available to provide cross checking of sensors to verify proper sequencing and provide operator side LED light indication. For additional information on SWITCHMAX®, please view the information online at www.pfa-inc.com.

PNP Low Profile PFA Proximity Sensor Wiring Instructions

EE70600/CT70600 Assembly





PFA Low Profile -PNP sensors (EE 70600/CT 70600 assembly with seal) function as typical high pressure proximity sensor, with a solid state device that senses the metal target of the lock or piston and outputs the input voltage (24VDC) to the machine control.

CT70600 Assembly Specifications
Part No. on Sensor:PFA-EE70600
Cylinder Designation:-PNP
Contact Type:Solid State PNP/NO
Contact Rating:100 mAmps @ 24VDC
Supply Voltage:10-30 VDC
Voltage Drop:≤2.5 VDC
Temperature:-13˚F (-25˚C) to 175˚F (80˚C)
Install Torque Max.:50 in-lbs. max.

Low Profile PNP sensors offer benefits to the user when fitting The KOR-LOK unit into demandingly small applications or when Integrating with other actuators using similar PNP sensor logic. PFA’s PNP option has a low voltage drop, typically allowing multiple sensors to be connected together to facilitate a single input to the machine control. Sensor integration is easily accomplished with PFA’s SWITCHMAX® connectivity solution with PNP designated splitter cables.


In a generic application the Normally Open Sensor is paired with an individual cable to provide power and route the signal. To use the sensors individually, Power +24VDC (Brown wire) and Neutral 0 VDC (Blue wire) is required, as well as some method of integrating the sensor signal (Black wire) to the press. Various schemes are used to accomplish this task for molds with multiple cylinders, however, PFA recommends SWITCHMAX® to provide a plug and play serial connection of sensors into single inputs for set and pull, while also providing operator side indication and troubleshooting capability.

While proper indication is expected, PFA cautions that for situations where a core or other part of the mold may be damaged if opened with cores set, it is recommended that a redundant sensor be placed on the core itself and wired in series with the main unit sensors to ensure the core is retracted prior to mold opening.

For details on SWITCHMAX® options, please view the information online at www.pfa-inc.com.

PNP Low Profile Sensor for PFA Hydraulic Locking Cylinders on Injection Molds - Main view

Sensor Replacement

Read instructions completely before beginning work. If you have questions or need technical assistance, please contact PFA for support.

WARNING! The sensor is not solid metal! Torque values are very low – in-lb not ft-lb!

The XLT Relay Sensor Assembly consists of the Sensor Body (EE70194), O-Ring Seal (2-013), and purple Loctite® (#545) thread compound. The Loctite® is provided to give the sensor resistance to loosening/leakage under normal use.

The XHT (High Temperature) Relay Sensor Assembly consists of the Sensor Body (EE70199), High Temp (VI) O-Ring Seals, Adaptor Body (LR08100) and purple Loctite® thread compound.

The PNP (Low Profile) Solid State Sensor Assembly consists of the Sensor Body (EE70600), O-Ring Seal (2-013) and purple Loctite® thread compound.

Preparation for Sensor Replacement

Ensure all hydraulic pressure is removed from the unit. Hoses may then be disconnected or the associated hydraulic system vented and secured to prevent pressurization of the KOR-LOK® Side-Action System Main Unit.

CAUTION! Fluid may eject from the sensor hole or ports under pressure or rod movement. Sensor is capable of handling Large Voltage and Current levels. Observe proper safety precautions.

Ensure the main unit is in a safe orientation so that the rod cannot move or apply a load on the cylinder, which might result in applied pressure to fluid still inside the unit.

Disconnect or secure power to the sensor from associated equipment.

Removal of Old Sensor

With pressure removed and vented and electrical power secured to the sensors, locate the front or rear sensor, as appropriate. Remove the cable from the sensor by unscrewing the retaining ring in a counterclockwise direction and unplugging the cable. For direct wire -XHT sensors, disconnect from power or controls.

Remove the sensor by rotating or unscrewing with a counterclockwise rotation on the hex nut connector (a 5/8” deep wall socket is recommended to avoid damage to the connector plug for XLT sensors). For PNP sensors, use a 5/8” or 16mm socket with cutout for cable.

Installation of New Sensor
(Recommended Preferred Method)

Inspect the sensor hole and surrounding sealing surface. Remove any debris from the surface, degrease threads, and ensure the surface is not damaged.

CAUTION! Sensor is designed to seal finger tight. Do not exceed 50 in-lbs (inch-pounds) of torque.

Degrease threads in housing and sensor. Ensure threads are clean and dry. If available, apply Loctite® Locquic® Primer T (7471) or equivalent to threads and wait until dry.

Add a small drop of purple Loctite® (#545) to the sensor threads and insert the new sensor in the hole turning clockwise. (Turn the sensor using fingers only until resistance of the o-ring seal is encountered – continue turning sensor clockwise against the seal resistance until the sensor seats on the sealing surface). The o-ring will seat with minimal torque and is fully seated by 30 in-lbs. At this level the sensor no longer turns freely.

Torque to 45 in-lbs (a 5/8” deep wall socket is recommended to avoid damage to the connector plug). EXCESSIVE TORQUE WILL DAMAGE THE SENSOR.

Connect cable and turn the connector retaining ring clockwise until play is removed or reconnect wire as appropriate.

Allow Loctite® to set for 5 minutes and reinstall KOR-LOK® unit in mold.

All PFA KOR-LOK®, DIE-LOK™ and Switchmax® application and use recommendations are advisory only. KL/DL preload force ratings are geometry dependent and based on PFA recommended sizing methods. Process variations may affect actual performance. PFA recommends use of PFA’s Switchmax® cross connected sensor checking and independent 2nd pull sensor (redundant) “core pulled” sensing on molds where opening with cores set could damage the mold. False readings in the event of single sensor failure, cylinder contamination, core to cylinder separation, attachment failure, etc. may occur. PFA is not responsible for situations arising from false sensor readings, product failure, misuse, or abuse – proper form, fit and function are the responsibility of the customer. PFA “Terms of Sale” apply.

These procedures have been written in an effort to address as many configurations as possible. If your particular application requires set up procedures that are not covered in the preceding documentation, please contact PFA at (262) 250-4410 for assistance.

Core Force Calculator

Please click here to be direct to the Core Force Calculator page for determining the force on the core due to injection pressure and the exposed core area.


Although most PFA products are built to size, the most critical items are maintained on-the-shelf for rapid availability. Need it to ship in 4 hours or less? We can do it! With real-time technical support, off-the-shelf products, and same day shipping, we can often have you back up and running before you've had your morning coffee. That's REAL SERVICE™.


We work with our customers to solve existing problems, and can design custom solutions when needed. With over 25 years of experience reviewing applications and providing custom products, PFA is likely to have the solution to your problem already designed. Call us today and see if we can help!


With a proven off-the-shelf "lean manufacturing" solution from PFA, your application works every time. Using a KOR-LOK® Side-Action System will result in shorter design and manufacturing time and will lead to shorter concept-to-production schedules. Quick Die Change (QDC) clamps are in-stock and ready to ship, so you can start saving time and money with SMED today. From spare parts to complex solutions, PFA is the answer to faster production and more profits.