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Plastic Clip and Fastener Designs

Lightweighting continues to remain a top priority for automotive manufacturers in order to help them meet strict fuel-efficiency requirements or to help get them one step closer towards getting the most mileage out EVs battery.  One way tiered suppliers are going about this is by redesigning traditional metal clamps with well designed injection-molded clips and fasteners.

Design engineering a plastic part to replace without compromising performance equires expertise in design, material, tooling, injection molding, and validation testing.  In this post, we’re going to explore some of the designs that have become the go-to for tier-1s and OEMs over the years.

Designs to Choose From

There is a vast library of different fastening clip designs automotive manufacturers can implement and optimize. Many of these designs include small, intricate features (such as the tree, hand-grip, and rib-cage designs) that are all subject to flashing and packing issues.  Without proper setup and precision tooling, these issues can lead to performance failures

Ultimately, it comes down to design.  Improper spacing between features, not enough material, too much material in some spots, etc. … all lead to parts that down operate or cannot be manufactured.

Below we’ve listed out some of the most common designs and what they’re typically used for. Each one has its pros and cons.

Tree Insertion Design

Tree insertion designs on fasteners and clips have long been used for body panel attachments of all kinds. It is well-known to be a strong design, capable of higher removal forces. An injection molder needs to work diligently to minimize insertion forces without compromising on retention capability.

The intricate features of the tree design require special attention to the spacing between features and areas where there may not be enough material vs. areas with too much material.


Butterfly Tab Design

Typically installed into panel holes, the ‘Butterfly Tab’ design is an Echo favorite.

This design is perfect for hard-to-reach places and areas requiring minimal insertion forces during the final installation. We don’t recommend this design for fasteners holding multiple, large lines. A tree design has higher retention.


Latch Design

A clip with the lid/latch and living hinge design is a very common method of retaining lines.  Latch designs make insertion easy, yet provides a reliable, strong hold. Adding multiple latches to a fastener is recommended when a fastener holds multiple lines.


Hand-Grip Design

This style of fastener installs onto a stud (screw). The design features great reliability ensuring low installation forces., but it’s a less attractive option for tight space though due to its larger profile.

Automotive clip design

Rib Cage Grip Design

Rib cage-style fasteners install onto a stud (screw). This design sometimes has larger insertion forces than the hand-grips design (above) but has a smaller profile than the hand-grips, making it a better option for tight areas.

Automotive fastener molder

Rabbit Ear Design

Lines install into this. Best for small diameter lines. Great for small areas.

When a fluid routing line is inserted into this type of fastening device, the rabbit ear flap area flexes down, allowing for easier insertion, and then spring back into place in order to retain the line.

bunny ear clip design

Wedge Clip Design

Fluid routing lines install into this design. It’s best for packaging small diameter lines together in bundles. Not as good for retention at the vehicle-level.


Wedge Clip with TPE Insert Design

This design includes an over-molded TPE material that helps with reducing NVH, and limits both rotation and translation of the lines. The wedge type design makes this clip a simple assembly, yet it also provides reliable retention once the line is inserted.


wedge clip with tpe for metal lines

TPE Grip

Commonly used in a lid-latch configuration. The TPE grip is great for reducing NVH, and limiting both rotation and translation. This design has higher retention forces than the Rabbit Ears w/ Grip, but it’s a little more complicated to assemble.

TPE Grip on clip



Overall, while these are some of the most popular and effective fastening designs being used in automotive applications, the rise of EVs and Hydrogen Fuel Cell vehicles continue to disrupt the industry.  We’re far from over with optimizing and rethinking the way plastic is used throughout a vehicle.

To see Echo & Ammex’s Design Innovations for yourself, head over to our Contact Us form to schedule time with our team.

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Automotive trends with plastics

Automotive Trends: Converting Metal Brackets to Plastic Clips

With the rise of Electric Vehicles and more demanding fuel efficiency regulation being mandated, is metal becoming a thing of the past?

Plastic is increasingly being used in place of metal for many different purposes. Specifically, plastic clips are replacing metal brackets used on automotive fluid routing assemblies as mounting supports for HVAC and brake lines. Plastic clips are perfect alternatives in these automotive applications and many more.

Why are manufacturers looking to convert more brackets to plastic?

  • Plastics cost less than metal and less costly to manufacture
  • Ability to manufacture more complex designs
  • Weight reduction

Plastic clips have multiple benefits. In the following, we discuss the top advantages of replacing metal brackets with plastic clips.

Plastic Clips Cost Less

There are a variety of reasons that factor into why plastic fastening devices cost less than their metal counterparts.  A few of the major factors include:


Because plastic is lighter weight compared to steel, injection molded clips will cost less as heavier weights typically equal greater costs.


Compared to most metal brackets, the process of injection molding clips is typically way less labor intensive.  Metal fabrication will most likely include a variety of additional steps, including: cutting, bending, welding, metal finishing prep, coating.  Each of those steps can add significant costs to the project.


Tooling for metal stamping and forming has a much higher cost than tooling for plastic. The tools needed for plastic can cost up to 50% less, a huge reduction in cost.

The tools for metal also wear more rapidly and need to be replaced more often than the tools for plastic, creating even more additional costs.


A commonly overlooked factor towards the overall cost of a metal bracket compared to its plastic counterpart is shipping & handling.

When transporting metals, protective shipping products must be used in order to prevent damage, unlike most plastic clips, which don’t need much protection during shipment.

A more important factor going towards shipping is that plastic weighs way less than steel brackets, which we’ll explore in this next section.


If you were to compare a part made of steel to the exact same part made from thermoplastic, the plastic version could be up to more than 6 times lighter! Design changes will most like need to be made in order to successfully replace a metal bracket with a plastic clip, but most likely, there will be a significant weight reduction.

For example, most automotive line clips you’ll find are made from Nylon 6/6.  Nylon 6/6 typically has a  density of 1.14g/cm3. Compare that to steel, which typically has a density of around 7.85g/cm3.

So, with lightweighting being an automotive megatrend that has become incredibly important for OEMs as new fuel efficiency regulations are mandated, it’s time to explore thermoplastic alternatives in order to improve a vehicle’s efficiency and performance.

Plastic Clips are Non-Corrosive

Another element that can easily get overlooked is that metal brackets are more at risk for corrosion issues.  This corrosion weakens the metals over time, causing them to be damaged, resulting in potential liability issues.  Plastics, on the other hand, won’t corrode and are less likely to suffer from a chemical exposure.

A common issue that has to be addressed with automotive HVAC lines is preventing galvanic corrosion. Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte.  In order to combat that with metal brackets, the tier-two bracket manufacturer or tier-one HVAC line manufacturer must also source a non-conductive EPDM grommet, which is an unwanted additional cost.

By converting to plastic, automotive manufacturers are able to avoid this issue completely with the correct clip.

Plastic’s Versatility

Plastic is an extremely versatile material, unlike metal. Plastic clips can be made into complex shapes and in a variety of different colors straight from the start. This makes them basically ready to go right out of the tool.

Unlike plastic, metal almost always has to go through several secondary processes before it is ready for installation. Metal brackets usually have to be cut or stamped, drilled, formed, pre-treated/cleaned, coated to prevent rust, packaged appropriately, etc.

Metal may also need multiple components added or installed such as a fastener or an isolator. With plastic, all of those can be built in, eliminating the need of multiple parts.

How to Make the Conversion from Metal Brackets to Plastic Clips

If you’re currently exploring the option of converting to plastic, you’ll want to make sure you work with  a partner that has experience across the product design, tool design, validation, fulfillment spectrum, and will:

  • Design from scratch to meet your needs or work with an existing design and suggest changes to ensure all specifications are met
  • Take the time to understand the assembly parameters and is able to design and perform comprehensive test plans to match real world applications
  • Use FEA software to optimize the clip’s mechanical properties and eliminate potential failure points
  • Use mold flow analysis and tool design improve product performance and meet tight tolerances

About Ammex Plastics and Echo Engineering

Ammex Plastics and Echo Engineering have been investing heavily with the automotive fastening market by developing a library of different designs, hiring plastics and process engineers, adding additional presses, and purchasing new testing and measuring devices.

We are experienced in designing and manufacturing a variety of different automotive clips used on HVAC lines, brake lines, harnesses, etc.

Thinking of making the switch from metal to plastic? If you are or if you have any other questions, visit our Contact page and send us a message! We have a team of technical experts ready to find the best solution for you.


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Ammex Launches Revamped website

Ammex Plastics Launches Revamped Website

Ammex Plastics, an Echo company, has recently launched their new, revamped website: ammexplastics.com. This site highlights the company’s automotive expertise and design capabilities in an appealing and organized format.  The website also features newly added educational blog section with a focus on technical injection molding and plastics content, as well as what’s new at Ammex and Echo.

Ammex Plastics’ focus rests on tight tolerances for automotive connecting, fastening, and suspension components that meet and surpass strict OEM requirements, which is what the revamped website highlights.

Connecting: One of the trickier parts to create is the barbed hose connector. Residual stresses can warp round parts, like hose connectors, after they are released from the mold. This is the reason early recognition of complicated connector designs is crucial!

Fastening: Ammex Plastics has been tooling up and supplying plastic clips and fasteners for 20 years, has shipped millions of parts, and runs a PPM rate of <2.

Suspension: Ammex is highly experienced in molding complex suspension components, such as: striker caps, spring isolators, and jounce bumper assemblies.

Ammex Plastics, based in Monroe, MI, was founded in 1999, and later acquired by Echo Engineering & Production Supplies, Inc. in 2017. The updated website should make your inquiries and research much easier. The Request a Quote portion of the site allows you to fill out a form and attach a print/drawing of the part to help speed up the quoting process. Ammex Plastics is dedicated to working with you every step of the way and if there are any questions head over to our Contact Us page.

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The burden of hose connector part design and design for manufacturability has shifted from the OEM to the tier-1 supplier and their injection molding partner.  Throughout this post we’ll discuss the reasons behind this shift, what makes a fluid connector technically complex, and the expertise your molding partner needs to deliver a stable and repeatable part.

Design Responsibilities Shifts to the Tier-1 Suppliers

Engineering resources at automotive OEMs have shifted away from “classic” part design and toward strategic priorities, such as electrification.  As a result, the burden of part design and design for manufacturability is falling more and more to you—the tier 1 supplier—and your injection molding partner.  Since so much production has gone to low-cost countries it’s even harder to find a molding partner with local expertise in part design, tool design, and processing.

Automotive Barbed Hose Connector Specs Tighten

Fluid routing specs have really tightened over the past decade.  OEM teams tend to ratchet up roundness and concentricity specs every time an end-user failure occurs.  Now the specs on connectors are much higher than the hoses that they attach to!

It’s Challenging to Produce Round Plastic Parts To-Spec and On-Budget

Injection molding is a dance between quality, cycle time, and cost.  All three are tightly wound together.  Experienced tool designers and molding partners will tell you that it’s really tricky to produce round parts.  It looks easy but plays hard.  This is because residual stresses in the part can make it challenging to hit the specs, which can lead to longer cycle times to let the part cool, which can increase the cost.

Residual stresses can warp round parts (like fluid connectors) after they are released from the mold.  This can be offset by exotic materials and longer cooling cycles, but that also drives up cost.

Early Recognition of Complicated Fluid Connector Designs Is Crucial

Some design elements can make a fluid connector very tricky to produce on-time, on-budget, and to-spec. These include varying wall thicknesses, sharp transitions in geometry, small port sizes, and unreasonably tight tolerances/ GD&T specs.

The trick is to spot these very early in the quote process, and a top-notch molding partner will do just that. Catching it early is key because small changes to part design can avoid headaches down the road. These headaches can include very long PPAP time lines, high PPM rates, and having to ask the OEM for a deviation.

Injection Molding Tool Design Can Offset Complex Geometries

Hopefully most recommended design tweaks can be accommodated.  If not, an experienced injection molding partner can overcome many challenges through tool design.

Quality tool engineers can balance melt flow and reduce cycle times with hot runner systems, increase cooling capacity with copper cores and forced air flows, and produce precise round parts with out-of-round tools (what??).  Yes, you read that correctly.

Depending on the part design, material flow, and residual stresses, sometimes it takes an out-of-round tool to produce precision round parts like fluid connectors.  Molding partners that don’t know this can set themselves and their customers up for a very long and hard journey.

Finding the Right Injection Molding Partner

If getting the fluid connector done right is your primary driver, then make sure you choose the right molding supplier.  If they aren’t asking you lots of questions about wall thicknesses, sharp transitions, knife edges, tolerances & technical specs, gate locations, and materials, then they probably are not doing an in-depth part feasibility up front.  That should send off warning bells.

Ammex Plastics has been tooling up and supplying hose connectors for 20 years, has shipped millions of parts, and runs at a PPM rate of <2.  If you’re looking for a new or alternate molding partner, head over to our Contact Us page today, and we’ll get back with you ASAP.

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Echo Engineering Brings $2.4 Million & 60 Jobs to Michigan-Based Location

Indianapolis, Ind., – Echo Engineering is investing $2.4 million into 60+ full-time jobs with additional real estate and automated manufacturing equipment in the recently acquired plastic injection molding facilities in Michigan.

The two facilities, located in Monroe and Frenchtown Township, are expected to grow by 30% in the next year with the support of Echo’s investment and a $210,000 performance-based grant received from the Michigan Business Development Program.

The investment focuses on providing additional operations capacity including injection molding machines with automated robotics, increasing warehouse facility capacity, and growing teams to support the daily operations at the Michigan locations.

“To date, since we made the acquisition, in the first six months we have added 21 full-time positions, and we have already invested more than $1.0 million.” – Kingdon Offenbacker, CEO

Echo Engineering acquired Ammex Plastics in October 2017 to create additional manufacturing capabilities to its customers. The full-service plastic components manufacturer primarily supports the automotive industry for custom plastic component technologies including clips, mounts, and fittings for fluid routing, fastening, and suspension systems.

The Michigan Business Development Program is part of an incentive program from the Michigan Strategic Fund, and is in cooperation with the Michigan Economic Development Corp. This program supports local businesses, including manufacturing facilities, by pushing for growth within the state in hopes of creating job opportunities.

Echo Engineering and Production Supplies, Inc. is a design and engineering business that develops and manufactures direct and indirect product. Echo’s Core Solution delivers risk reduction, product development speed, and ultimately a responsive commitment to customers’ design & engineering process, supply chain capacity, and manufacturing process.

Core Product Technologies are focused on Sealing, Connecting, NVH, Fastening, and other customer focused products. Echo is headquartered in Indianapolis, IN with additional locations in Monroe, MI; Milpitas, CA; Shanghai, China; and Guadalajara, Mexico.

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Echo Engineering Broadens Capabilities by Acquiring Ammex Plastics

Echo Engineering and Production Supplies, Inc. announced today the recent acquisition of Ammex Plastics, a full-service plastic components manufacturer based in Monroe, MI.

Echo, headquartered in Indianapolis, IN, serves world-class companies in diverse industries by providing them with both custom and catalog parts which focus on masking, protecting, and hanging, as well as rubber and plastic OEM components aligning with five core competencies – connecting technology; sealing technology; fastener, clip, and tie technology; housing, class A static and dynamic technology; and NVH management technology.

Echo has experienced exceptional growth over the last decade and looks forward to accelerating this success with a manufacturing facility located in the heart of the automotive industry. Ammex Plastics, located just 40 minutes South of Detroit, is a full-service plastic injection molding supplier primarily serving the automotive industry by manufacturing fluid routing, fastening, interior, and suspension system components – including clips, mounts, fittings, fasteners, isolators, bumpers, and quick connects. Moving forward, Ammex Plastics will operate under Echo’s umbrella, as Echo Engineering and Production Supplies, Inc. DBA Ammex Plastics.

Echo’s product offerings are expansive and the industries they serve are diverse. The organization offers solutions that focus on customer needs, ultimately enhancing overall efficiencies, and they are devoted to providing support to their customers from design to implementation.

“Ammex Plastics sets the bar when it comes to providing quality components, ensuring peace of mind for their customers resulting in an unprecedented customer retention rate.  This has always been and will continue to be a key success factor.” – Kingdon Offenbacker, CEO.

Echo is committed to taking the time to understand what role a component plays in the user’s manufacturing process – building partnerships and changing expectations is, at its core, what The Echo Way is all about.

Ammex is recognized for producing quality products that align seamlessly with Echo’s core business strategy. Echo’s extensive resources, coupled with Ammex’s domestic injection molding capabilities, will allow Echo to expand both its product offerings and its customer base, as well as their market share within the automotive plastics industry. (AND/OR a quote here from Kingdon about being excited about what Ammex can add to our ability to serve our customers.) Acquiring Ammex Plastics is an investment Echo is excited to make in order to broaden their ability to deliver peace of mind to their customers – another imperative aspect of The Echo Way.

About Ammex Plastics

Founded in 1999 and located in Monroe, Mich., Ammex Plastics, LLC is an ISO 16949/TS 16949:2009 registered full-service manufacturer of custom plastic components. Ammex Plastics has two Monroe facilities, one production facility and one warehouse, each with more than 15,000 square feet. The production facility operates 17 presses with 3 additional presses order, and the facilities are supported by 47 full-time employees. Ammex has differentiated itself from competitors by being a customer-oriented injection molding solutions provider, while maintaining topnotch quality of less than 0.5 PPM (parts per million).

Services and Capabilities

Ammex Plastics’ core and secondary operations include the following:

  • Engineering and Product Design

  • Custom Injection Molding (Prototype to Full Production)

  • Insert Molding

  • Assembly

  • Over Molding

  • Hot Stamping

  • Decorating Operations

  • Production Pad Printing

Markets Served and Products Produced

With facilities conveniently located near Detroit, Ammex Plastics primarily serves the automotive/mobility and industrial markets. Ammex mainly produces fluid, fastening, interior, and suspension system components – including clips, mounts, fittings, isolators, bumpers, and quick connects.

About Echo Engineering and Production Supplies, Inc.

Since 1966, Echo Engineering and Production Supplies, Inc. has served world-class companies in diverse industries by providing them with both custom and catalog parts which focus on masking, protecting, and hanging, as well as rubber and plastic OEM components aligning with five core technologies.

Echo has an extensive selection of materials available that meet various performance requirements, and Echo’s operations include multiple stocking locations (Indianapolis, IN; Milpitas, CA; and Guadalajara, Mèxico), in-house converting, and extensive molding capabilities. Echo maintains their 97% customer retention rate by providing strong support in engineering, manufacturing, quality (ISO 9001 certified), and logistics to meet customer requirements and exceed expectations.

Services and Capabilities

Echo Engineering’s core and secondary operations include the following:

  • Engineering and Product Design

  • Injection Molding

  • Compression Molding

  • Transfer Molding

  • Extrusions

  • Over Molding

  • Lathe Cutting

  • Die Cutting

  • Texturing

  • Sub-Assembly

  • Custom Formulation and Mixing

  • In-House and 3rd Party Testing

  • 3D Rapid Prototyping

Markets Served and Products Produced

Echo has a diverse and loyal customer base, serving numerous industries, including automotive/mobility, construction, electronics, fluid power, lighting, marine, metal finishing, and powersport. Echo’s capabilities and product offerings are focused on masking & protecting (tapes, caps, plugs, custom), sealing (gaskets, o-rings, charge port caps), connecting (bellows, boots, air admission hoses, quick connects), managing NVH (grommets, pads, shims), fastening (clips, fasteners), housing (air flow housing, enclosure, light lenses), and class A technologies (engine covers, vanity covers, foot pedals).

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