What quality tests does Carosung perform on metal bag hardware?

Carosung offers different minimum order quantities depending on whether the product is available from stock or requires customization.

Stock Hardware

The standard MOQ for selected stock hardware is 50 pieces per design, subject to stock availability and product requirements.

Selected stock items may also be customized with laser-engraved logos, depending on the product and logo design.

Customized Stainless Steel Hardware

The standard MOQ for customized stainless steel products is 200 pieces per design, subject to the product structure, manufacturing method, and finishing requirements.

Customized Zinc Alloy Hardware

The standard MOQ for customized zinc alloy products is 500 pieces per design, depending on the mold, structure, and production requirements.

Complex or Special Designs

Products with complex mechanisms, multiple components, special materials, or demanding finishing requirements may require a different MOQ. These projects are evaluated individually.

Pricing and Multiple Finishes

Unit prices generally vary according to order quantity, material, manufacturing process, surface finish, and packaging requirements.

For projects requiring multiple colors or finishes, the feasibility and minimum quantity for each finish should be confirmed separately. Using the same mold may avoid the need for an additional mold, but other finishing or production charges may still apply.

Contact us with your design, estimated quantity, and preferred finish for a project-specific quotation.

Color consistency is managed through surface preparation, process control, approved reference samples, and appropriate inspection methods.

Surface Preparation and Process Control

Polishing and other surface preparation steps influence the appearance of the finished hardware. Consistent preparation helps reduce visible differences caused by surface roughness, scratches, or uneven reflections.

For PVD coating, relevant process parameters are controlled according to the coating system and equipment. For electroplating, factors such as bath chemistry, process conditions, and finishing steps influence the final color and appearance.

Approved Color Samples

Before mass production, customers can approve a physical sample representing the desired finish. This sample can then serve as a reference for production and subsequent orders.

For repeat orders, retaining approved samples and production records helps compare the appearance of new batches with the previously accepted finish.

Managing Repeat Orders

Different production batches may show some variation because of differences in materials, surface preparation, or processing conditions. Our aim is to maintain consistency with the approved reference sample and the agreed acceptance criteria.

For particularly color-sensitive projects, customers should confirm the master sample, acceptable color variation, and inspection method before mass production.

Carosung uses a structured quality control process covering incoming materials, manufacturing, surface finishing, and final inspection.

1. Incoming Quality Control (IQC)

Incoming materials and components are checked against the applicable purchase specifications and project requirements. Depending on the material and order, checks may include visual inspection, dimensional verification, supplier documentation, or material testing.

2. In-Process Quality Control (IPQC)

During manufacturing, inspections can be carried out at relevant stages to monitor dimensions, surface condition, and production consistency.

The inspection points depend on the product's manufacturing process and critical quality characteristics.

3. Surface-Finishing Inspection

Finished hardware can be checked for color, appearance, visible defects, and other agreed requirements. Where specified and appropriate, additional testing can be arranged for coating thickness, adhesion, or corrosion resistance.

4. Final Quality Control (OQC)

Before shipment, finished products undergo final inspection according to the agreed specifications and acceptance criteria. Relevant checks may include dimensions, surface appearance, assembly, and functional operation.

5. Documentation and Continuous Improvement

Inspection records and retained reference samples can support quality comparison and investigation of potential issues. Material traceability and supporting documentation are maintained according to the product, supplier records, and project requirements.

Our quality control process is designed to reduce defects and maintain consistency. Specific inspection plans and acceptance criteria can be agreed before production.

Custom mold development typically involves design review, engineering assessment, mold manufacturing, trial production, sample evaluation, and final approval.

Step 1: Design Review and DFM Assessment

Customers can provide sketches, reference images, technical drawings, or 3D CAD files.

Our engineering team reviews the design for manufacturability, including wall thickness, draft angles, corner radii, structural strength, assembly requirements, and material flow where relevant. Recommended modifications can be discussed before tooling begins.

Step 2: Mold Design and Manufacturing

After the design is confirmed, the mold is designed and manufactured using suitable machining processes. Depending on the geometry, these may include CNC machining and electrical discharge machining (EDM).

The tooling structure and manufacturing method depend on the selected material and production process. Zinc alloy die-casting molds, for example, are designed differently from tooling used for stamping or other metalworking processes.

Step 3: Trial Production and Sample Evaluation

Initial trial parts are produced and checked for dimensions, structural features, surface quality, and assembly requirements.

Where adjustments are necessary, the mold or product design can be revised before final sample approval.

Step 4: Surface Finishing and Approval

Trial parts can be polished and finished in the proposed color for customer evaluation. Physical samples allow customers to review the appearance, dimensions, fit, and function before authorizing mass production.

The best surface finish depends on the base material, desired color, product structure, expected wear, corrosion requirements, applicable regulations, order quantity, and budget. PVD coating and traditional electroplating each have suitable applications.

PVD Coating

Physical Vapor Deposition (PVD) is a vacuum-based coating process used to create functional and decorative surface layers.

Depending on the coating system and application, PVD can offer good surface hardness and wear resistance. It may be suitable for selected hardware components that experience frequent contact or friction.

Available colors may include gold, rose gold, gunmetal, matte black, and metallic silver, depending on the substrate and coating process.

Actual performance depends on the base material, surface preparation, coating system, and processing conditions. Testing should be specified where particular performance requirements apply.

Traditional Electroplating

Electroplating is widely used to achieve metallic colors and decorative finishes. It can provide bright, reflective surfaces and a broad range of color options when the substrate and finishing process are suitable.

Possible finishes include gold, silver, bright nickel, chrome, and other agreed colors. The exact appearance and performance depend on the plating system, underlayers, surface preparation, and any protective topcoat.

Electroplating can be appropriate for decorative hardware as well as selected functional components. Its suitability should be assessed according to the intended use rather than assuming it is only for low-wear applications.

Vintage and Textured Finishes

For brands seeking a heritage or understated appearance, options may include antique gold, antique bronze, antique copper, antique silver, satin, brushed, and sandblasted finishes.

Two-tone effects and protective topcoats may also be considered where technically feasible.

How to Make the Right Choice

We recommend evaluating appearance, wear requirements, corrosion resistance, material compatibility, regulatory requirements, production volume, and budget together. Where necessary, samples and agreed testing criteria can be used to evaluate the selected finish before mass production.

The right material depends on the intended use, required strength, weight, corrosion resistance, appearance, manufacturing method, and budget. Different materials offer different advantages.

Stainless Steel

Stainless steel grades such as 304 and 316 are commonly considered for hardware requiring good corrosion resistance and durability.

Grade 316 generally offers better resistance to chloride-related corrosion than grade 304, although actual performance depends on the environment, surface condition, and material grade.

Stainless steel is often suitable for functional hardware, rings, hooks, buckles, and components that require a solid metallic feel. Its weight, machining requirements, and finishing options should also be considered.

Brass

Brass is valued for its substantial feel, machinability, and distinctive appearance. It can be suitable for premium decorative hardware and selected functional components.

Depending on its composition and environment, brass may tarnish, oxidize, or develop a patina over time. Appropriate finishing can help achieve the desired appearance and performance.

Zinc Alloy

Zinc alloy is widely used for decorative and functional hardware with complex shapes, detailed logos, and three-dimensional designs. Die-casting can be an efficient manufacturing method for suitable geometries and production volumes.

It is often considered for bag locks, logo plates, buckle heads, and decorative fittings. The suitability of zinc alloy for load-bearing applications depends on the component design, alloy, manufacturing quality, and required mechanical performance.

Aluminum

Aluminum is valued for its relatively low density and can be useful when reducing product weight is important. Its strength, surface hardness, and corrosion performance depend on the alloy, component design, and surface treatment.

How to Choose

For a practical material recommendation, share the product drawing or reference image, intended application, approximate dimensions, required finish, target quantity, and budget. Our team can then assess suitable material options for the project.