Footwear construction methods

Introduction

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There are many different footwear construction methods, and each one has its own benefits and drawbacks. In this article, we will discuss the most common methods and how they relate to the choice of sole material. We'll also take a look at some of the newer construction techniques that are starting to gain popularity. So whether you're a shoemaker just starting out, or you're simply curious about how your shoes are made, read on for a comprehensive guide to footwear construction!

Direct moulding / direct injection

Some sole materials may be directly moulded to the upper part of the footwear – an operation which both forms and attaches the sole at the same time. The footwear is placed in a mould, the sole material is injected into the mould, and then it hardens to form a bond with the upper. This construction method is commonly used for sports footwear as it can create a very strong and lightweight sole.

One disadvantage of this construction method is that it requires the factory to have the correct machinery to support this process which is a major financial investment. Another disadvantage is that it can be difficult to achieve a good fit, as the footwear needs to be placed in the mould perfectly in order to avoid any gaps or overlaps. In addition, this method is not suitable for all sole materials – for example, EVA foam which is a material that expands after being injected, and therefore requires a different kind of mold. In this article we go more in depth about Compression molded EVA

Open mould pour casting

This footwear construction method uses an open mould (as opposed to a closed mould used in direct injection) into which the sole material is poured. The footwear is then placed in the mould and the sole material hardens around it. Once the sole has hardened, it is removed from the mould and any excess material is trimmed away.

This construction method is commonly used for footwear with thicker soles, as it allows for a more even distribution of material. It is also less expensive than direct injection as it does not require specialized machinery.  However, it can be difficult to achieve a precise fit with this method and there is also a risk of the sole material not bonding properly to the upper.

Sidewall stitched construction

In this footwear construction method, the sole is stitched to the upper using a strong thread (such as Kevlar or polyester). The stitching goes around the entire perimeter of the footwear, creating a very strong and durable bond. This construction method is often used for heavy-duty footwear such as work boots, as it can withstand a lot of wear and tear. This construction methods is also commonly used to attach rubber "cup-soles" to leather uppers in casual court shoes.

Goodyear welted construction

In this footwear construction method, the upper is attached to the sole using a welt (a strip of leather or rubber that goes around the perimeter of the footwear). The welt is then stitched to the sole, creating a very strong bond. This construction method is commonly used for formal footwear such as dress shoes, as it creates a very sleek and professional look.

Autoclaved Footwear consctruction

In this footwear construction method, the shoe upper is placed in a special chamber (known as an autoclave) together with pieces of rubber where they are exposed to high pressure and high temperature. The heat curese the rubber and fuses the various parts together creating a strong bond. Prime examples of these kind of shoes are rubber boots or classic canvas shoes such as converse or vans.

Blake stitched construction

In this footwear construction method, the sole is stitched to the upper using a single thread (rather than a welt). The stitching goes around the entire perimeter of the footwear, creating a strong and durable bond. This construction method is often used for casual footwear such as sneakers, as it is less expensive than Goodyear welted construction.

Bonded construction

In this footwear construction method, the sole is attached to the upper using an adhesive (cement). The footwear is then placed in a machine that uses high pressure and heat to fuse the sole material to the upper. This construction method is commonly used for sports footwear as it creates a very strong bond between the sole and upper.

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Summary

In this article we have gone over the different footwear construction methods, as well as their advantages and disadvantages. We hope that this guide has helped you better understand the different options available to you when choosing footwear.

Don't hesitate to reach out to us whenever you have a footwear project in mind, we'd love to hear more about your ideas and learn how we can turn them into reality.

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