Articles By Jonathan

CNC Trimming of Thermoformed Parts

CNC Trimming of Thermoformed PartsFive-axis CNC trimming produces parts with repeatable, close tolerances. There are several ‘keys’ to achieving consistent and accurately trimmed parts, but first a description of the equipment and trimming process.

CNC trimming equipment has been described as a ‘Computer controlled router’. This simplistic description does not do justice to the extensive capabilities of this important element in creating precision thermoformed parts. In addition to routers, trimming tools include end mills, circular saws and drills. Countless subset variations of these tools are used to overcome the most complex challenges of part trimming.

Plastic part trimming can be done on Five-axis as well as Three-axis trimming centers. Tru-Form Plastics uses only Five-axis CNC’s to trim thermoformed parts. The Five-axis are identified as X-Y-Z (length-width-depth) with two additional degrees of freedom sometimes referenced as C & B.Tru-Form Plastics Five-axis trimming centers are 5’x10′ with 28″ of Z axis clearance. The table size is either 5’x10′ solid or two 5’x5′ tables that can act independently for load/unload, or ‘slaved’ to act as a solid table.

As previously mentioned, thermoformed parts can be produced on either male or female forming tools. It is critical that the CNC trim fixture always duplicates size/configuration of the part’s forming tool. In other words, the trim fixture will look identical to the forming tool. The next key is to hold the part securely and immobile while it is being trimmed. Tru-Form Plastics accomplishes this by use of a vacuum system to lock the part against the trim fixture. The vacuum lock down system is so positive that additional clamps or nests are rarely needed. This allows full freedom for trimming on the non-tool side of the part. Parts formed on female tools can utilize formed features that are then CNC trimmed open so the trimmed surface is not visible from the outside of the part.

Part design revisions involving trimming can be easily accomplished with a CNC program change. Similarly, multiple part configurations can be generated from a single formed part by different trim(s).

CNC trimming summary

Part size Up to 5’x10′ with up to 28″ depth
Trim equipment All CNC’s are Five-axis with integral tool changers for economical trim cycles and enhanced safety.

Engineering & Quality

Engineering & QualityTFP’s engineers can provide advice and technical support to fit your every need by helping create and execute solutions to solve problems of form, fit and manufacturability. Our engineering and quality staff work closely with our clients and the entire TFP team to ensure that the end product meets the needs of the user and the marketplace.

Engineering: Our engineers have built an atmosphere of “out of the box” thinking to provide technical and quality suggestions to meet or exceed our clients’ needs for dependability, cost and manufacturability. This results in a partnership with each of our customers, which starts at the pre-production phase. We work with you to analyze your projects to identify cost-savings opportunities as we integrate quality and confirm manufacturability.

Quality: TFP’s extremely skilled and experienced QA department fully reviews the quality requirements that we document and monitor throughout the process. Utilizing a full range of measurement equipment including FARO Arm®, color measurement, digital calipers, tint meters and many other state-of-the-art equipment we promote uniform dimensional accuracy, structural integrity and cosmetic consistency throughout all in-process and finished parts and assemblies.


  • Understanding customers’ design requests and assisting from conception to completion.
  • Complete reviews of customers’ projects and designing outlines for tolerances, material requirements, drafts, undercuts and detailed features.
  • Experts in material selection and function.
  • Modern quality equipment i.e.: Ultrasonic thickness gauges, OHM Meters, Gloss & Tint Meters and a FARO Arm®

New Additions:

TFP is investing in and will soon have 3-D rapid prototyping helping create true-to-life parts of any kind with superb accuracy. This addition will show the smallest details for functional, fit and form testing, allowing for your design verification.

TFP continues to add state-of-the-art equipment to help us provide the best services available to you, our customer.

We will soon have a thermoforming simulator which provides a detailed and accurate prediction of what will happen during the forming process before you cut the tool or scrap expensive material.

Adding these capabilities will help you reduce design time as well as reduce possible expensive trial and error processes.

TFP Excels In:

  • Operating with integrity as we pursue the best interests of our customers.
  • Production start up through first article.
  • Immediate attention from engineering and quality involving any non-conformance.
  • Providing in-process and final inspections to customers for ease of mind.
  • Quality and engineering departments are committed to total quality management from production to final inspection.

Mold, Fixture & Tool Building

Mold, Fixture & Tool BuildingIn-house tool making capabilities

Producing a satisfactory and successful part always starts with the design and construction of an excellent tool. This is true in thermoforming as well as many other processes.

At Tru-Form Plastics, we consider the initial information exchange with the customer to be a critical phase in the project. Our engineers will want to know the part end use parameters to assist in determining the best tooling design and material selection for the application. These factors will go beyond expected volume, to include stressful environments such as chemicals, impact and temperature. We will want to know the part(s) relationship with mating parts, so features can be designed in to reduce assembly costs and improve product functionality.

The thermal efficiency and durability of aluminum make it the material of choice for production thermoforming tools. The nature of thermoforming combined with the longevity of the aluminum tool can yield an unlimited number of production parts. Aluminum tools with adequate temperature control will produce parts efficiently, with dimensional stability, and repeatable appearance from run to run.

Tru-Form Plastics constructs their machined aluminum thermoforming tools in-house based on customer supplied 3-D CAD part files. This capability provides economic advantages along with reduced lead times to tool completion. Also important, in-house tool making provides control during this crucial stage of the product development cycle.

In some instances, such as early market evaluations, considering a temporary or prototype tool may be advisable. Tru-Form Plastics engineers will be able to explain the tradeoffs of temporary tooling compared to going directly to a production tool for your application.

Assembly & Fabrication


Tru-Form Plastics, Inc. is a “Turn-Key” manufacturing facility with many plastic molding processes, trimming, metal machining and finishing of individual components as well as providing fabrication, bonding and assembly of multiple parts. The TFP team has years of valuable experience in providing finished parts that require delicate, complicated and precise fabrication and assembly.

Our goal is to provide the most complete part possible at a competitive cost and speed to market. From your initial design, TFP will be able to take your idea, mold or machine it, paint, assemble custom pack and ship it.

We use our experience to offer an entire compliment of assembly and packaging services including bar coding that strategically align with your business objectives. TFP project experts have the knowledge and capability starting from your initial design to the final production stage, ensuring complete fit, form and aesthetics of each assembled product, all under one roof.

TFP Excels In:

  • Multi-Part Assembly
  • Die Cutting
  • Hardware Installation Gluing/Solvent Bonding
  • Heat Welding
  • Sonic Welding
  • Painting – one of the few on the West Coast
  • Silk Screening – Easy Secondary Operations
  • Customized Packaging to Prevent Damage

Painting & Printing

page-printing-largeTFP’s in-house painting department provides a variety of applications using state-of-the-art equipment. Our painting experts use the latest techniques to apply the coating per your specifications. Special templates and fixtures are designed to cover parts over the areas that do not require paint. These detailed forms contour the required surfaces thus streamlining the prep and masking process.

Because of our commitment to EPA and AQMD regulations, TFP is one of the few painting houses permitted by the State of California to perform shielding applications with nickel and copper. In fact, TFP is UL approved and certified for application of said materials on certain substrates. While adhering to AQMD permissible standards for higher VOC’s, we encourage application of 1.0 VOC paints across all materials to promote GREEN.

TFP has developed and maintains a very close relationship with major paint suppliers. Due to these relationships, we are able to obtain immediate responses for color matching and a quick delivery of paint. We also have the ability to test in-house for color, gloss and surface resistivity to meet all your requirements.

TFP Excels In:

  • Application of various types of paint including water bourne & polyurethanes
  • Smooth Finishes
  • Surface Texturing
  • EMI Shielding
  • Specialty Masking and Fixturing
  • Peel off Protective Coating
  • Multi Color Silk Screening
  • Pad Printing
  • Sand Blasting

Thermoforming Process (step-by-step)

thermoforming-thumb-200Vacuum Forming Plastic Process (step-by-step)

  • A material blank which has a length and width greater than the finished part is loaded into a clamp frame to be carried through the process.
  • The blank in the clamp frame moves into an oven where it is heated to the forming temperature. At the forming temperature, the material is softened and pliable, but remains in a sheet configuration and is not melted.
  • The material is then moved from the oven to the forming station. The softened blank is then sealed on the deck of the tool. In some instances, low pressure air will prestretch the material to enhance wall thickness uniformity on the finished part.
  • A vacuum is drawn between the blank and tool to form the softened material against the tool surface. In pressure forming, while the vacuum is drawn to avoid air entrapment, positive air pressure is applied on the non tool side of the material to force the material against the tool surface.
  • An option for the process when using female tools is to use a ‘pusher’ or ‘plug assist’ on the non tool side of the blank to control and improve material distribution in the finished part.
  • The (now) formed part, while still in the clamp frame, is removed from the forming tool.
  • The clamp frame releases (opens) for part removal.
  • The formed part is now ready for the next step – trimming.

Plastic Process Comparison

The chart below compares thermoforming in the first two columns of vacuum forming/pressure forming with reaction injection molding, injection molding and structural foam molding. The highest value is 10 and lowest is 1. Thermoforming also competes with rotomolding, blow molding, fiberglass, and sheetmetal fabrication.

Vacuum Forming Pressure Forming RIM Injection Molding Structural Foam
Part Cost 8 7 6 10 7
Tool Cost 8 9 5 1 5
Process Pressure 9 8 5 1 5
Part Mfg Cycle 5 6 6 10 8
Machine Cost 7 6 5 2 4
Material Types 7 8 2 10 9
Maximum Size 8 7 6 2 6
Residual Stress 8 7 9 1 5
Process Pressure 8 6 5 1 3

Thermoformer Tru-Form diversifying into aerospace market

iso_cert_small01[1]By Roger Renstrom
June 11h, 2013

Custom thermoformer Tru-Form Plastics Inc. of Gardena, Calif., has positioned itself for additional aircraft business as a complement to its strength in housings for medical gear.

For the medical and aerospace markets, “the common denominators are quality, moderate volume, low tool cost and short lead time,” said Jack Schrieffer, sales manager.

Tru-Form decided in September 2011 to begin an ISO certification process, in part to expand its market opportunities providing parts to original equipment manufacturers and replacement suppliers for aircraft interior and galley applications.

To gain the credentials, Tru-Form invested slightly more than $100,000 for consulting fees, registrar procedures and project-related employee time en route to certification to ISO 9001:2008 and AS 9100:2009 in accordance with the requirements of aerospace-oriented AS 9104A.

The effort involved reviews of Tru-Form’s quality management system including procedures and controls, employee training, process documentation, implementation of process metrics and pre-audit assessments.

National Quality Assurance USA of Acton, Mass., issued the certification to Tru-Form on Feb. 4. NQA conducted a preliminary review in the fall of 2012 and a three-day audit starting Jan. 2. NQA is a trading name of Ascertiva Group Ltd., a subsidiary of the London-based Electrical Safety Council.

In conjunction with the advance, “we went to a new computer operating system that was helpful for the ISO certification process but not strictly for this purpose so related costs are not included in the $100,000,” Schrieffer said.

Currently, Tru-Form’s largest end markets are medical test equipment enclosures and panels and transportation components for recreational vehicle, automotive aftermarket, marine, motorcycle and golf cart applications.

Also, Tru-Form has a lighting business that includes lenses, reflectors and other components for indoor and outdoor commercial lighting fixtures.

Tru-Form has listings with UL LLC, the safety science and standards development firm, for specialized capabilities to shield materials and substrates of electronic equipment from waves causing electromagnetic interference and radio frequency interference.

Tru-Form occupies 50,000 square feet and operates six ZMD International Inc. machines. Four are dedicated for vacuum forming, and two have capabilities for both vacuum and pressure forming.

Recently, Tru-Form decided to remove from storage, and revamp, a Drypoll-made pressure forming press. Tru-Form aims to begin operating that seventh press in July.

Tru-Form operates two DMS and two MotionMaster computer-numerical-control trimming centers. Each has five-axis capability and a standard-size table of 5 feet by10 feet. Tru-Form uses the tooling centers for tool builds and the machining of metal and plastic parts.

Established in 1956, privately-owned Tru-Form employs 35 including two programmers for CNC machines and tool-build processes and, typically, one or two operators for the tooling centers.

For the five months ended May 31, Tru-Form recorded 2013 sales growth of more than 18 percent versus the comparable period in 2012, Schrieffer said.

Aerospace certification will support all business lines

iso_cert_small01[1]Aerospace certification will support all business lines
By Clare Goldsberry
As published in Plastics Today: July 24th, 2013

Tru-Form Plastics, Inc. (, a thermoformer of custom components for the aerospace, medical diagnostic equipment, transportation and lighting industries, announced the company’s certifications: ISO 9001:2008 and AS 9100:2009 in accordance with the requirements of AS 9104A (Aerospace).

Tru-Form sought the Aerospace Category certification as part of its on-going commitment to and history of supplying aircraft components, including aircraft interior and galley parts. The certification comes as the company announced plans to significantly expand its support of the aircraft interior market. Company officials said the aerospace requirements for documentation and strict adherence to quality standards supports the requirements of its quality-minded customers in a broad range of industries.

Jack Schrieffer, Tru-Form’s sales manager, said that obtaining ISO certification is more critical to a company’s success today than ever before. “ISO is multifaceted and it’s not something that a company can do after-the-fact,” he told PlasticsToday. “If you want a problem-free part it starts with the part design, not when you begin making the part itself. At Tru-Form, we want you to understand the process and the limitations of the process. Getting the part designed right – designed for the process, for manufacturability – is critical.”

Considerations for part design, said Schrieffer, include the end-use application such as where will the part be used and how will it be used. “We’ll help you come up with the design features with the long-term in mind,” he added.

Both ISO and AS certifications can also help a company become an approved supplier in a shorter period of time, which is beneficial to both companies, Schrieffer noted. “What we’ve found is that while a lot of companies still want to do an audit to ensure our suitability as a supplier, the audits may only take a half-day rather than three days or longer,” he said. “The fact that we’ve gone through the rigors of the 17-month process for ISO and AS certification means they can sign off on doing with us with the confidence that we can fulfill their requirements for quality from design to finished part. ISO and AS certification isn’t just a calling but part of the whole quality equation.”

Tru-Form, a privately held company established in 1956, is located in Gardena, CA, occupying a 50,000-sq-ft facility. The company is capable of forming parts up to 5 x 9 ft trimmed on 5-axis CNC trimmers to ensure optimum aesthetics and precision fit.

Tru-Form Plastics Receives ISO 9001:2008 and AS 9100:2009 Certification

iso_cert_small01[1]The management and employees of Tru-Form Plastics, Inc. are proud to announce we have received ISO 9001:2008 and AS 9100:2009 certification. The registrar, NQA of Acton, Ma issued the certificate on February 4th, which is valid until February 4, 2016. A copy of the certificate is attached.

The AS 9100:2009 certification is in accordance with the requirements of AS 9104A (Aerospace). Management chose to pursue meeting the standards of the aerospace criteria for several reasons. The aerospace requirements for documentation and strict adherence to quality standards is highly regarded from a quality and industry perspective. Meeting the aerospace requirements is readily recognized by quality minded customers outside of the aerospace industry.

To become ISO 9001:2008 and AS 9100:2009 certified, Tru-Form Plastics underwent a 17-month evaluation process that included a review of the company’s quality management system (QMS), management system review, employee training, process documentation, establishment of process metrics and pre-audit assessments to ensure an optimum QMS with accompanying procedures and controls.

We trust you will agree that the certification is not only a strong commitment to meeting the quality standards, but also a major step forward in enhancing service to our valued customers.

For further information please contact or call 310/327-9444.