DFM Checklist:

Start with a clear, detailed drawing

A complete gasket drawing is the foundation of any successful project. Well-prepared drawings give clear instructions for what you need for your parts and create a more collaborative dialogue with your supplier. In turn, your supplier can provide more thorough, tailored guidance early on for your custom gaskets. 

Here are a few key details your drawing should include:

• Concise dimensions (with units and tolerances)
• A material designation for your desired base polymer
• 2D views of the part from multiple angles
• Any relevant technical specs or performance requirements

Want to know everything your drawing should include for quick, accurate quotes? Read our Custom Gasket Design Checklist.

Define application requirements

Before manufacturing, be clear about how and where the gasket will be used. For example, you should try to address relevant application questions, including:

• Is the seal static or dynamic (stationary or moving)? 
• What are the operating temperatures for the application?
• What chemicals or environmental factors will it face? 
• What are the specific load parameters for the application?

Defining these parameters upfront helps in selecting the right material and manufacturing method. The more you communicate about the gasket’s real-world conditions, the better your supplier can work with you in tailoring the design for both immediate manufacturing success and long-term performance.

Plan for practical, efficient manufacturing and minimal waste

A little design forethought can improve material yield and save cost. 

• Consider the standard material stock sizes for your gasket. For instance, sheet rubber often comes in common thicknesses. If you can adapt your gasket to fit those sizes, you can potentially avoid more complex manufacturing needs or wasted material needed for non-standard thicknesses or sizes. If not, you may need to consider custom molding to achieve precision manufacturing for non-standard shapes and sizes.
• Is nesting an option? Sometimes when multiple gaskets are being designed for a particular application, parts can be “nested” inside one another to optimize material yields. Put simply, gaskets may be designed in a way where die cutting can produce several parts with one punch of the die.

Leverage prototyping

You don’t necessarily need to invest in expensive hard tooling before testing your initial design. Certain suppliers can help you take advantage of dieless cutting (also called flash cutting) or other table cutting methods to create prototype gaskets without dedicated dies. 

This prototyping approach allows you to test your initial design without spending thousands on tooling. For example, Timco can assist customers with the validation of their gasket design through small trial runs which allows for testing and changing designs prior to mass production.  

Die Cutting

The go-to method for many flat gaskets. Die cutting uses a custom steel die to stamp out parts from sheet material, like a big, industrial cookie cutter. This approach makes it efficient for a wide range of sizes and shapes. Die cutting is often limited to thickness of up to .5“ and thicker materials can be subject to “dishing” or concavity during the cutting process.  

Design tips: Limit gasket thickness to .5” or less and consider standard size thicknesses for your application. More standard sizes (.062”, .125”, .25”, etc.) typically allow better economies of scale due to availability of sheet material.  

Kiss Cutting

A specialized form of die cutting used mostly for adhesive-backed gaskets. Kiss cutting is meant to cut through a sheet of material, without cutting through the backing liner. The result is a gasket cut to shape, but the adhesive liner remains intact. The result creates a sort of “sticker” gasket that’s easy to peel and apply.

Design tips: If your gasket has a pressure-sensitive adhesive (PSA) backing, plan for kiss cutting so the production staff can easily peel off the adhesive liner. Consider including a small pull tab or uncut section of the liner in your design. This detail can be easily overlooked, but will make liners much easier to remove when it’s time for assembly.

Rotary Die Cutting

Ideal for high-volume production, rotary die cutting uses a cylindrical die on a rotating drum to cut parts at high speed. This method is efficient for continuous rolls of material, rapidly producing large quantities of identical clean-cut parts. 

Design tips: Rotary die cutting can handle intricate shapes at volume, but that efficiency comes with some notable considerations. Try to avoid extremely unique features that could shift out of place at high speed. Your material of choice must also come in roll or coil form instead of flat sheets. 

Dieless Cutting (Flash/Knife Cutting)

Various machines can use a CNC-controlled knife, laser, or water jet to cut gasket shapes without a physical die. This dieless method is perfect for prototypes, low volumes, or very large parts that might normally require an expensive die. 

Design tips: Because no tooling is needed, you have flexibility to experiment with complex geometries or fine-tune dimensions. This process also gives you flexibility to test your designs when you’re in early development or need just a handful of gaskets to prove out a design.

Lathe Cutting

In lathe cutting, an ID/OD rubber sleeve is forced on to a mandrel. The rubber sleeve is then spun at high speed while a specialized blade slices off cross-sectional rings. This can produce seamless rings with very precisely toleranced diameters and thicknesses. 

Design tips: Consider lathe cutting if your gasket construct is a simple ID/OD ring. Small chamfer features can also be added via a lathe cut process. This process is ideal for high volume, tightly toleranced parts. 

Molding

Some gaskets are best produced by molding (compression, transfer, or injection molding techniques), especially if they have three-dimensional features, need a non-standard thickness, require rubber-to-metal bonding, or have some other complexity. Molding involves creating custom tooling which often involves the creation of a cavity (or multiple cavities) that are machined to mirror the shape of the part. The tool is also constructed in a way that allows rubber to flow into the cavity and cure to the desired shape.

Design tips: When designing for gaskets which have features that align well to a molding process,  be mindful of possible budgetary restrictions related to the upfront tooling cost. Die cut tooling is often significantly more economical than a multi-cavity mold. If some features of the part can be changed to align with a die cut process, there are both economical and lead-time related benefits that could result from simple design changes.  

Choose the right adhesive for the surface

There are many types of gasket adhesives (acrylic, rubber-based, heat activated tape systems (HATS), , etc.), each suited to different surfaces and conditions. Each of these can be the right choice depending on your applicating surface.

• What is the surface material (metal, plastic, glass, etc.)?
• Is the surface smooth or textured? 
• Will there be surface contaminants (oil, grease, etc.)?
• Is the surface exposed to high or low temperatures?

Addressing these factors will play an important role in identifying an adhesive that will cut and adhere properly. With this information, Timco can present options for different pressure sensitive adhesives tailored to your custom gaskets.

Design for easy liner removal

A common issue with adhesive-backed gaskets is making sure the backing liner can be easily peeled off the final part. If a gasket is cut cleanly all the way around, production staff can struggle with grabbing and pulling on the liner. To avoid this, consider incorporating the following features: 

• Kiss cutting can create an extended-release liner that extends from the gasket where the die does not cut through the adhesive layer, creating a little flap for removal. 
• Split liners use a scored backing to make it easier for assembly workers to peel liners away in sections.

The exact solution can depend on your gasket design and end use. Discuss these options with your supplier and consider them in your design to help streamline the assembly process and make life easier for end users.

Adjust manufacturing methods base on adhesive

When you review your design with Timco, expect some discussion on adhesive choice. Sometimes a high-strength adhesive is necessary for function, but you may want to consider modifying your part layout or cutting method accordingly. The bottom line is to treat the adhesive as an integral part of the design, not an afterthought, to optimize manufacturing.