Quality Control

The purpose of this document is to provide quality standards and serve as a guideline to insure proper application of these standards to all adjusting rings manufactured for LADTECH, Inc. LADTECH quality technicians will also adhere to these standards.


The Ladtech adjustment rings are manufactured from 100 percent-recycled plastic. Raw material for processing into moldable plastic flake is selected and purchased based on certification provided and the supplier’s reputation for providing consistent containment-free raw materials. The predominant source product for our raw plastic is post-consumer, blow-molded milk jugs and detergent bottles. These products are initially manufactured from High Density Polyethylene as identified and verified by American Engineering Testing, Inc. completed in 1996, to be compatible before integration into the process.


The reclaimed material is first shredded to a uniform size, and then goes through a series of wash cycles to clean and float off any labels or foreign materials. The cleaned plastic is then dried, sized to a moldable flake and all fines and dust are removed by aspiration. The selected materials are blended utilizing a 900-pound capacity conical blender. The blended material is then stored in poly bags inside gaylord containers. The melt value of each batch is verified. Each batch is assigned an identification number and identified by date blended and actual melt value. The containers are tagged as to batch number. This information is kept on file for any subsequent tracing needs. This material is now ready to be injection molded. The material batch number is then recorded on the job sheet when production run is made.


The reclaimed material is first shredded to a uniform size and then goes through a series of wash cycles to clean and float off any labels or foreign materials. The cleaned plastic is then dried, sized to a moldable flake and all fines and dust are removed by aspiration. The reclaimed material is then stored in poly bags inside gaylord containers weighing approximately 750 pounds when filled. These containers are identified and logged by date, source, and reclaim line process parameters (line speed, wash and dry cycle times and water temperature). Any stored gaylord container will only contain material of a similar melt flow index and density value. This material is now ready to be injection molded.


All reclaimed material will be tested on a procurement/production batch basis as necessary to verify the following property values:

Property Test Method Acceptable Value
Melt Flow Index ASTM D-4976 4.0 to 10.0 g/10 min.
Density ASTM D-792 .941 to .965 g/cm2
Tensile Strength, yield ASTM D-638 2.0 to 5.0 103lb/in2

If a blend formula is changed by more than 5% it will be retested to assure compliance with above. When blending is done, processing characteristics necessary to produce a quality part must be maintained. This will be verified by the static compressive testing done on the production parts.


All molding will be done on quality production type injection molding tooling. This tooling will be consistent with current manufacturing and safety standards. It will be designed to consistently produce a quality product capable of meeting and exceeding our established quality and performance standards.


The LADTECH rings will be injection molded using good manufacturing practices consistent with current technology and the type of injection molding machine being utilized. Product requirements, materials being molded and ultimately, the safety of the operator and any personnel in the immediate vicinity will guide the process.


Will be established for each part number. This sheet will identify the mold, the injection-molding machine of preference and list all the machine processing parameters that have been established for the run start-up. It will also contain operator instructions pertinent to size gauging, visual inspection requirements and testing requirements, along with any known quality alerts.

A JOB SHEET will be maintained for each production run and become a permanent part of the manufacture’s records. This job sheet will be assigned an identification number and will list:

  • Subject a stack of HDPE rings to direct contact with hot-mix asphalt concrete.
  • Part Identification Number
  • Actual Date(s) of production run
  • Mold Identification Number
  • Material Identification Number
  • Injection Molding Machine Identification Number
  • Date coding of parts being produced
  • Operation identification
  • Shift number
  • Initial machine settings and any subsequent adjustments
  • Start-up Quality Check after machine is run in (Verify that part meets specifications)
  • In Process Quality Check (Verification that process is maintaining specifications)
  • Last Shoot Inspection (Final Verification of run)
  • Final record of All Machine Settings (Record of any changes in process from initial setup and adjustments)
  • Record how parts were palletized and stored
  • All pallet stacks shall be identified by production sheet number


  • The Ladtech rings will be stacked on their specifically designed pallets with the male tongue up on round product and down on square and rectangular product. The pallets will be designed to afford maximum support, keeping the rings from deforming due to the natural tendency of plastic to “creep”.
  • The rings will be secured to the pallet by not less than binding loops of 3/8″ poly strap. Edge protectors will be used on the upper ring to protect the outer edge from being damaged by the strap.
  • The catalog number and count will be clearly marked in white 1″ high letter on the outside of each stack on two opposing sides.
  • Each pallet stack will be identified by its production run job sheet number.
  • The pallet stacks will be stored on a reasonably flat surface in such a manner as to prevent damage from handling or deformity. Pallet stacks to be stored allowing access with fork truck when loading a truck.


  • Trucks will be loaded per the ship ticket and any special instructions.
  • Each pallet will be checked for proper identification and tight straps.
  • Each pallet stack will be carefully handled while moving and loading a truck.
  • Each pallet stack will be positioned and secured to assure safe, damage-free transportation and safe, easy unloading.
  • A Bill of Lading will be completed on each shipment and a list attached indicating the appropriate production job sheet for each pallet stack.

Manufacturing Specifications and Tolerance

1 .250 MAXIMUM allowable deviation from flat (dish or bow)
2 .250 MAXIMUM allowable vertical ribbon effect (convolution) As measured around the outer edge with the part turned top down on a known flat surface
3 .125 MAXIMUM allowable horizontal ribbon effect (bulging between ribs) As measured at the largest outside point and compared to the point where the outer wall intersects the rib sections

1 ± .125 on diameter of length dimensions as shown on part control drawings
2 ± .063 on height dimensions as shown on part drawings for parts to 2″ in height
3 ± .125 on height dimension as shown on part drawings for parts over 4″ in height

1 Part to be completely filled – on voided areas.
2 No cracks or separations at knit lines.
3 No cracks or tears from part ejection hang-ups.
4 No protrusions from broken ejector pins.
5 Ripples or sags on vertical walls to cover no more than 10% of the surface.
6 Color to be consistent dark gray or black (Derived from the addition of 2% carbon black and any residual color from the recycled materials).
DATE: January 1, 2001 – Replaces any previously issued specifications.

Any rings found not meeting quality standards will be reground and reprocessed into quality product. The cause of this quality deviation will be identified and remedied immediately.

The Ladtech HDPE adjustment rings shall meet and exceed the static load requirements of ASSHTO Highway Bridge Specifications HS-25 (21,280 Pounds). The Ladtech HDPE adjustment rings must withstand 1,000,000 plus full load cycles of 10 seconds or less duration. The Ladtech HDPE adjustment rings must perform without failure to a minimum of 150 percent of these load values.


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Manufacturing Specifications and Tolerance

The following data was developed by LADTECH personnel utilizing the plastic laboratory of Hennepin Technical College, Brooklyn Park, MN in June of 1998.
Melt Index D 4976 .49 G/10 min.
Density *Estimated .94 – .96 G/cm2
Tensil Strength @yeild D 638 3,453 PSI
Elongation @yeild D 638 122 %
Flexural Modulus D 790 147,771 PSI
Izod Impact Strength D 256 7.12 Ft-lb/in
Hardness (shore D) D 2240 63.1
Head Deflection Temp D 648 174°F @66 PSI
Shrinkage D 955 .032 in/in
The above data is representative of LADTECH primary-use blend polyethylene. This blend is produced from 100% recycled polyethylene. The predominate source product for the raw plastic is curbside collected, post-consumer, blow molded milk jugs, detergent bottles and injection molded thin-wall containers. The material is shredded, washed, dried, and sized to LADTECH specifications.

Designs and Specifications 
24″, 27″, 30″, 32″, 34″ & 36″ Diameter Rings
24″ x 24″ and 24″ x 36″ Catch Basin

THICKNESS/HEIGHT OPTIONS AVAILABLE: (dependent upon diameter as follows)

  • 24″ & 27″   1 1/4″, 1 1/2″, 2″, 4″, 1/4″ Spacer, and 1 1/2″ Slope
  • 30″   1 1/2″, 2 1/4″, 4″, 1/4″ Spacer, and 2 1/4″ Slope
  • 32″ & 34″   2″, 3″, 1/4″ Spacer, and 2 1/4″ Slope
  • 36″ 1 1/4″, 2 1/4″, 3″, 1/4″ Spacer, and 2 1/2″ Slope
  • 24″x 36″ Catch Basin   1 1/2″, 2″, 2 3/4″, 1/4″ Spacer, and 1 1/2″ Slope
  • 24″x 24″ Catch Basin  1 1/4″ , 1 1/2″, 2″, 2 3/4″, 1/4″ Spacer and 1 1/2″ Slope and 2 3/4″ Slope