Understanding the different shoe manufacturing methods is crucial for making informed decisions when outsourcing your shoe production and to devise a shoe quality control plan. Each shoe manufacturing method has its own unique advantages and disadvantages. Here, I explain five of the most used techniques in factory.
Cemented Shoe Construction
Cemented construction is a popular method for producing casual and fashion shoes. This technique involves attaching the shoe’s upper to the outsole using adhesive. It is cost-effective and simple, making it ideal for mass production as it requires fewer skilled artisans. During the final inspection, it is essential to check the strength of the attachment. Ensure that the adhesive is applied correctly—neither too much, which can affect the shoe’s appearance, nor too little, which can compromise the bonding strength.
Goodyear Welted Shoe Construction
The Goodyear Welt method is renowned for producing high-quality and highly durable shoes and boots. This technique involves stitching a leather strip, known as the “welt,” around the upper and the insole, which is then attached to the outsole. You can easily identify Goodyear welted shoes by the two rows of stitching: one on the inside where the upper edges meet, and another around the outer sole.
Producing Goodyear welted shoes requires skilled artisans due to the complexity of the process, making these shoes more expensive than others. During quality inspections, it is crucial to check that the stitching is even and the bonds are strong. Inspectors also ensure the symmetry and alignment of the shoe’s form, maintaining the high standards expected of this construction method.
Blake Shoe Construction
Blake construction is commonly used for formal shoes. Similar to the Goodyear method, it involves stitching the upper, insole, and outsole together. However, unlike Goodyear construction, Blake shoes do not have a welt; instead, the outsole is directly attached to the insole. This method is typically handcrafted by experienced artisans, making it more expensive to produce.
During quality control inspections, the focus is on ensuring the consistency of the stitching and the proper alignment of the shoe’s parts. Inspectors also check the shoe’s structural integrity and aesthetic appeal to maintain high standards.
Direct Injection Shoe (DIP) Construction
Direct Injection Shoe (DIP) construction is often used for work boots and outdoor shoes due to its durability and support. In this process, the footwear upper, midsole, and outsole are molded together using a machine that injects materials at high pressure into the shoe’s mold. This method creates a seamless shoe with no stitched parts, providing high production efficiency and consistent quality once the molding process is properly set up. Typically, this method is used in larger factories that have the necessary machinery and skilled workers. Quality control for direct injection shoes begins at the initial stage, ensuring that the sample produced by the mold is correct and approved. The molding process must be set up precisely and correctly to maintain high standards.
Vulcanized Shoe Construction
Vulcanized shoe construction is commonly used for sneakers and canvas shoes. In this method, the shoe’s rubber outsole is attached to the upper using heat and pressure. Vulcanization is cost-effective and offers a fast turnaround time, making it a popular choice for many brands. During the quality control process, it is crucial to identify any defects caused by the heat and pressure during the attachment and vulcanization processes. Ensuring the materials are not adversely affected by these processes is key to maintaining the shoe’s quality.
For footwear, the strongest results come from a quality assurance program that covers every stage of production, often with an experienced footwear technician on site. It starts with incoming materials QC: checking all incoming materials before they enter production.
Before and during production, pre-production meetings with the factory team and the artisans align everyone on the production plan, quality standards, potential issues and the techniques skilled workers must follow.
The first batches produced should be inspected in detail before full-scale production continues. In-process QA then monitors each step, from cutting and stitching to lasting, so issues are fixed immediately.
Finally, pre-shipment QC is a final inspection of the finished products before they are shipped.
Training is part of quality too. Learning sessions for factory QC staff and supervisors, face-to-face workshops on quality standards and inspection techniques, and 1:1 coaching on the shop floor all build a culture of quality and continuous improvement.
Process improvement across departments removes the waste and inaccuracies that lead to rework or rejects: precise cutting for consistency, better stitching for durability and appearance, and a refined lasting process so the final shape and fit are consistent.
In the pre-shipment inspection of footwear, inspectors follow a AQL chart for the product sampling. The inspection procedures include a thorough examination of the final workmanship. Inspectors perform various tests, including fit tests and size measurements, to confirm that the shoes or boots fit correctly and comfortably. The strength of bonding between the upper and the outsole is checked to ensure durability, and inspectors verify the alignment of the shoes to maintain aesthetic and structural integrity. The inspection process also involves a detailed review of the stitching to ensure it is even and secure, and inspectors check that all materials are correctly inserted according to the design specifications.
Footwear needs inspectors with a real background in footwear technology. The right quality plan depends on the type of shoe and how it is made, and the major shoe-making hubs in China, India, Malaysia and Vietnam each have their own strengths and habits.
If you sell footwear online and can’t visit the factory yourself, I can help you design a practical quality plan, and coordinate inspections on the ground through a trusted quality service partner, so your shoes earn good reviews.
Tell me about your product and what’s worrying you. I’ll reply personally with practical next steps, and you’ll also receive my free buyer’s quality guidebook.
Pre-shipment inspection is the best practice to manage the quality of production if you are buying a significant quantity of products. Normally buyers spend 3-5% of cost of product in pre-shipment inspection. The benefits of pre-shipment inspection include but not limited to the following:
There are several parties can help to perform pre-shipment inspection and the pros and cons are illustrated as below:
| Pros | Cons | Best Practice |
Third party inspection company | – Impartial – Only represent you – Resourceful – Professional – Good after sales service – Systematic – Clear whistle blower channel | – Not worth for low shipment value
| If your shipment is worth more than USD 4,000 or if you have faced quality problem before, it is worth to buy inspection service from third party inspection company |
Sourcing/Trading Company | – Can be focus – Resourceful – Good after sales service
| – Usually they represent both buyer and factory – Not professional in quality control | If your shipment value is lesser than USD 4,000, you may delegate the inspection job to sourcing/trading company by setting up a good resolution contract |
Individual/Freelancers | – Lesser cost – Can be professional – Can be flexible | – Lack of systematic approach – Vary service quality depends on the individual’s ability – Risk of no after sales service | If you have been introduced to a trustable individual/freelancer and you have done the due diligence. |
Factory self-inspection | – Save cost – Professional in product making | – Potential of negligence as no other perspective to check the quality – Conflict of Interest | If this is a continuous lot of production, there is no significant changes of production and no quality issues in first shipment. Occasional inspection by third party is advice. |
KOL Quality is the knowledge site of Hazel Kwong, a manufacturing and quality expert who has worked in Shanghai, mainland China, Malaysia and now Hong Kong. Hazel shares practical advice for buyers and always stands on the buyer’s side. When a buyer needs work on the ground, she coordinates it through a trusted quality service company and partner laboratories in China.
First, agree the product requirements and checking criteria, ideally with an approved golden sample. When you place the order, share your supplier’s contact and production schedule with your inspector so they can follow up and book the inspection at the right time. A pre-shipment inspection should be done when 100% of the goods are produced and at least 80% are packed. If you’d like help setting this up, ask me.
A pre-shipment inspection should be done when 100% of the goods are produced and at least 80% are packed. For a first inspection, allow about 5 working days to plan the checking criteria and book the inspector.
Inspection companies have standard checklists for most product categories, but every product and brand is different. The best criteria combine a standard checklist with your own requirements, your approved sample and the issues your customers care about. I’m always happy to review your checklist with you.
You will normally get the pre-shipment inspection report within 24 hours in working days (Monday to Friday).
You’ll usually hear about a failed result on the day of the inspection. Don’t panic, and don’t ship. Review the defects, then agree a resolution or rework plan with your supplier, followed by a re-inspection. If you need help talking to the factory, ask me. I’ve had these conversations many times.
