Surface Texture: High-Quality Parts with Precision

The final appearance, tactile feel, and functionality of your product are significantly influenced by the surface texture you choose as a product designer.

However, it’s important to understand that producers use a specific lingo to create and describe surface textures. Understanding these phrases and how they are used can help you avoid misconceptions, as well as save you time and money while you build your product. Let’s first examine the significance of surface roughness and know more about surface texture.

At Sungplastic, we have strong capacities to help with your projects of surface treatments.

What is Surface Texture?

Surface texture, in the context of manufacturing, refers to the three-dimensional characteristics of a solid’s topography. Since achieving a perfectly flat and featureless surface is not possible, all surfaces possess some form of texture.

Why is Surface Texture Significant?

The texture of a solid plastic or metal component greatly influences its mechanical properties and functionality. Texture affects factors such as friction, corrosion, heat transfer, wear, and more. For instance, highly rough surfaces enhance grip for handheld parts but would be unsuitable for use as bearing surfaces.

Textures are often employed creatively, such as concealing manufacturing defects like parting lines on plastic injection molded enclosures. Others are used for cosmetic purposes, simulating the appearance of wood, stone, or leather. Lastly, surface texture plays a vital role when preparing for subsequent processes like painting or anodizing.

How to Describe Surface Texture?

When it comes to describing surface texture, there are specific terms that engineers and product designers should be familiar with in order to effectively communicate with manufacturers during product development.

Lay

Lay refers to the overall direction of a surface pattern. It represents a large-scale or global pattern created by the manufacturing process, such as milling, grinding, or sanding.

Waviness

Similar to lay, waviness is caused by the movement of the machine tool over a larger area. It results in a waveform pattern that is influenced by cyclical and repeating vibrations transferred to the workpiece.

Roughness

Roughness is a topic that often leads to potential misunderstandings with our clients. It pertains to the finest scale of measurement and arises from the interaction of the cutting tool or abrasive with the surface in a more random and chaotic manner.

Roughness is typically quantified using a value called Ra. This value is calculated by measuring a specific sample length using a delicate probe or stylus called a profilometer. The profilometer’s sensitive tip is moved across the surface of the feature, perpendicular to the lay of the texture. It records minute variations, from which the average height deviation from a nominal flat line is determined. A lower Ra value indicates a flatter or finer surface. For more information on how Ra works, you can visit Sungplastic’s services.

Is Ra the Only Consideration?

Remember, Ra solely provides information about random, localized points above the average plane of the surface. There are various manufacturing methods that can achieve the same Ra value while resulting in distinct surface finishes.

If you require a specific pattern for your parts, it is advisable to submit a sample for testing. This allows us to assist you in achieving a matching texture on the surface. We hope this information has been helpful, and if you require further guidance on selecting the appropriate surface finish for your next project, we have additional advice available.

Measurement and Evaluation of Texture

Surface Profilometers
Surface profilometers are instruments used to measure and analyze surface texture parameters. They use contact or non-contact methods to collect data, allowing for the quantification of surface roughness, waviness, and other texture attributes.

Contact vs. Non-contact methods
Contact methods involve physical contact with the surface being measured, while non-contact methods, such as laser or optical profilometry, do not physically touch the surface. Each method has its advantages and limitations depending on the application and material.

Standards and Tolerances
Surface texture standards and tolerances are critical in ensuring product quality and performance. Various industries have established standards for acceptable surface texture parameters, which help manufacturers meet specific requirements and customer expectations.

Factors Affecting Texture

There are some factors affecting the parts texture, including manufacturing processes, material properties and environmental conditions.

Manufacturing Processes

Machining
Surface texture can be greatly affected by machining processes such as turning, milling, and drilling. The choice of cutting tools, cutting speed, feed rate, and depth of cut all influence the resultant surface finish. Faster cutting speeds and smaller feed rates typically lead to smoother surfaces, while slower speeds and larger feeds can result in rougher finishes.

Grinding
Grinding is a precision machining process used to achieve very tight tolerances and fine surface finishes. The abrasive grains in grinding wheels remove material to create a desired surface texture. The choice of grinding wheel, grinding speed, and coolant plays a critical role in achieving the desired surface finish.

Polishing
Polishing is a finishing process that involves the removal of surface defects and imperfections to create a smooth and reflective surface. It is commonly used in the manufacturing of optical components, jewelry, and high-quality metal surfaces. Factors such as polishing media, pressure, and polishing duration impact the final surface texture.

Additive Manufacturing
In additive manufacturing (3D printing), surface texture is influenced by the layering process and the type of printing technology used. The layer height, print speed, and material properties all contribute to the texture of the printed object’s surfaces.

Casting, Forging, etc.
Casting and forging processes can produce a wide range of surface textures depending on factors like mold or die design, temperature, and material properties. The cooling rate during solidification in casting or the deformation processes in forging affect the final surface characteristics.

Material Properties

Hardness
The hardness of a material affects its surface texture. Harder materials tend to have smoother surfaces, while softer materials may exhibit more irregular textures. This is important in applications like metalworking, where the hardness of the workpiece impacts the ease of machining and the final surface finish.

Ductility
Ductile materials tend to deform plastically when subjected to stress. The ductility of a material can impact its response to machining, grinding, or other manufacturing processes, resulting in specific surface textures.

Elasticity
Elastic materials can recover their original shape after deformation. The elasticity of a material influences how it responds to manufacturing processes and how it maintains its surface texture under load or stress.

Surface Treatments
Various surface treatments, such as heat treatment, chemical etching, and coatings, can be applied to alter the surface texture of a material. For example, heat treatment can create a hardened surface layer with specific textures, while chemical treatments can etch patterns onto surfaces.

Environmental Conditions

Temperature
Surface texture can be affected by temperature fluctuations during manufacturing and service conditions. Thermal expansion and contraction of materials can lead to changes in surface roughness. Extreme temperatures can also cause thermal stress-induced texture changes.

Humidity
High humidity environments can lead to the formation of corrosion products or moisture-related surface changes. In some cases, this can result in surface texture alterations, especially in materials prone to corrosion.

Contaminants
Contaminants such as dust, dirt, and chemicals in the environment can adhere to surfaces, altering their texture over time. This is particularly important in applications like optics and electronics manufacturing, where even minute contaminants can affect performance.

Texture Modification

Surface Finishing Techniques

Polishing
Polishing is a common technique used to improve surface smoothness and reflectivity. It involves abrasion with progressively finer abrasives until the desired finish is achieved. Polishing is used in applications ranging from optics to jewelry.

Shot Peening
Shot peening involves bombarding a surface with small spherical particles to induce compressive stress and improve resistance to fatigue and stress corrosion cracking. The size and intensity of the peening process can control the resulting surface texture.

Electroplating
Electroplating involves depositing a thin layer of metal onto a substrate to improve its surface properties. It can be used for decorative purposes, corrosion resistance, or to achieve specific textures like a mirror-like finish.

Coatings and Surface Treatments

Anodizing
Anodizing is an electrochemical process used to create a protective and decorative oxide layer on metals like aluminum. The process can produce various surface textures, including matte, satin, or glossy finishes.

PVD/CVD Coatings
Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) are methods used to apply thin coatings of materials like metals, ceramics, or polymers to a substrate. These coatings can alter the texture, enhance wear resistance, or provide other functional properties.

Texture Control in Manufacturing

Controlling texture during manufacturing involves strict process control and quality assurance measures. Manufacturers must monitor and adjust machining parameters, tool wear, and surface treatments to meet specified surface finish requirements. Automation and advanced metrology tools play a critical role in maintaining consistent surface texture in mass production.

Applications of Surface Texture

Aerospace
In aerospace manufacturing, surface texture plays a crucial role in the performance and safety of aircraft components. Smooth and precise surface finishes are essential for reducing drag, improving fuel efficiency, and ensuring the integrity of critical parts.

Automotive
Surface texture is a key factor in automotive design and manufacturing. Engine components, transmission gears, and vehicle body panels require specific surface finishes to enhance efficiency, durability, and aesthetics.

Medical Devices
The medical device industry demands high precision and cleanliness in surface texture. Surgical instruments, orthopedic implants, and medical device housings must have controlled surface finishes to ensure biocompatibility and functionality.

Consumer Electronics
In the production of electronic devices like smartphones and laptops, surface texture affects both aesthetics and functionality. Smooth touchscreens, polished casings, and precise interfaces are crucial for user satisfaction.

Sungplastic’ s Services

Sungplastic is a China molding manufacturer, Specializing in manufacturing and dealing with custom plastics parts and metals parts or final products. Specific manufacturing services include CNC machining, injection molding, blow molding, overmolding and insert molding, compression molding, 3D printing, rapid tooling, etc. Surface finishing solutions include polishing, coating, anodizing, spray painting, color matching, etc.

If you are looking for similar services, please contact us.
Hope that our professional standards can help you to complete your project smoothly.

Related Resources:

Surface Finishes Services

SPI Injection Molding Standards

Thermoplastic and Thermoset Materials Used in The Injection Molding Process