surface finishing for cleaning and e-coating


After all aspects of the casting and machining are complete, we can apply aesthetic, functional and protective coatings.
We can meet various surface treatment requirements, include:
1. Bead blasting, tumbling, cleaning in-house

2. Chromating, Powder coating, Wet painting, E-coating, Anodizing, etc. via our high and stable performance suppliers nearby our factory

3. ROHS, REACH compliance



Measurement instrument for surface finishing parts
Salt Spray tester
thickness meter for testing the thickness of painting parts
Thickness tester
Color meter for testing the painting parts
  • Colorimeter

    Bringing Designs to Life With more than 10 years’ experience, Sunrise Metal has been dedicated to providing one-stop aluminum manufacturing solutions, integrated superior rapid prototyping, tooling and die casting, along with CNC machining and surface finishing through state of the art machinery and processes . We bring your designs to life one stop here at Sunrise Metal with quality and reliability by professional and fast way.


If you got any questions, please do not hesitate to send us a message. We reply within 24 hours.


Surface Finishing has equal importance like the rest of the processes involved in the manufacturing of metal parts. It can give your parts a better look and acts as a protective shield. That can significantly increase the durability of your parts.


Sunrise Metalcan provide you with an aesthetic and cost-effective Surface Finishing solution. This guide is aimed to give you a proper understanding of surface finishing and our capabilities in this field.


For any additional queries, you can contact our customer support. We will be glad to help.
What is Surface Finishing?


Surface Finishing is the different industrial processes used to modify the properties of the surface of manufactured parts. Surface Finishing processes can improve appearance, corrosion resistance, hardness, electrical, and thermal conductivity of parts.


Surface Finishing can also help repair several surface defects of manufactured parts. Proper surface treatment can ensure better protection from environmental and chemical effects, thus increase the longevity of parts.


Any industries dealing with metal parts manufacturing have diversified use for the multiple types of surface finishing techniques. Sometimes improving the properties of a cheaper material with a functional surface finish can be cost-effective as well.


Sunrise Metal can ensure a high-quality and aesthetic surface finish for your parts. If you want a one-stop solution to your manufacturing needs, you can rest assured as we relentlessly work to provide our customers with the best quality possible.

What are the different Surface Finishing processes?

Surface Finishing can be classified into these categories based on how it works with the manufactured parts. They are,


  • Adding or Altering Finishing
  • Removing or Reshaping Finishing
  • Mechanical Finishing


Adding or Altering Finishing is done by applying or depositing an additional layer of material on the parts. It can be done in many ways. So, it is further classified into several other categories such as,


  • Anodizing
  • Powder Coating
  • Burnishing
  • Electroplating
  • Electroless Plating
  • Chromate Conversion Coating
  • Galvanization (Hot-dip Galvanizing)
  • Shot Peening etc.


Removing or Reshaping Finishing is done by getting rid of excess metal for smoothening the rough outer surface of a metal part. It can be further classified into the following categories.


  • Abrasive Blasting (Sand Blasting)
  • Electropolishing
  • Shot Blasting
  • Grinding
  • Laser Engraving
  • Tumbling
  • Polishing etc.


Mechanical Finishing is basically those type of finishing that is done by using abrasives. Some of the removing finishing can be considered as mechanical finishing. Such as,


  • Sand Blasting
  • Burnishing
  • Grinding
  • Tumbling
  • Polishing etc.


As you can see, surface finishing is a very broad sector. There are a huge number of ways to provide surface finishing for your parts. This guide aims to give you some idea about the fundamentals of different surface finishes.


What are the advantages of Surface Finishing?

Surface Finishing is a significant part of the manufacturing process of any part. It can greatly improve the quality and durability of the parts. Let’s look at some of the advantages of Surface Finishing.


Aesthetic Outlook


Different surface finishing techniques will yield parts with different looks. What type of finishes can be applied mostly depends on the type of material used for finishing. Surface finishes may serve both decorative and protective purposes for the parts.


But Surface Finishes that serves a decorative purpose is equally important as those that are used for protection. Because the outlook of something is a major decision driver regarding its purchase. Consumers will naturally choose things that look better.


Corrosion Resistance

Metal parts are very vulnerable to corrosion or oxidation damage due to various environmental and chemical effects. That will hinder the performance and durability of parts and possibly collapse the entire machine in the process.


Most of the surface treatment processes are desired to have a corrosion resistive properties in them. Because this a common issue that causes damage to metal parts, especially parts that made of ferrous metals.


Wear Resistance

Moving metal parts that remained in harsh environments and subjected to heavy loadings may be damaged due to wearing. This is a common phenomenon in automobiles and robots that makes use of moving parts.


Wearing becomes severe when the surface roughness is too much and causes additional friction in the parts. Some protective surface finishes can reduce the surface roughness that will improve the wear resistance of the parts.


Improved Conductive properties

Surface Finishing can provide a conductive or insulated surface for metal parts. The surface roughness has some impact on the electrical and thermal conductivity. Surface Finishing can significantly increase the electrical and thermal conductivity of parts.


Surface Finishing can also provide shielding for electronic parts inside a metal enclosure. This is made conductive coatings very popular in the electronic industry.


Reduced Surface Roughness

The surface Roughness of metal parts can be significantly reduced by proper surface finishing. It will reduce the friction in metal parts, thus reducing the chances of wear and tear in parts. So, this will increase the durability of your parts.


This is especially important for some leading industries such as the automotive, aerospace, and robotics industry. They utilize many moving metal parts in their products. Because surface roughness is a major issue for them that is overcome by proper surface finishes.
Do I need Surface Finishing for die castings?

Die Casting is a sophisticated process for mass production of metal parts. One of its major advantages is that die-cast parts have a very nice surface finish to it. That often reduces the need for additional surface treatment.


But, that doesn’t entirely diminish the need for other surface treatment process. Even if it already has a good looking surface finish, most manufacturers will prefer an additional layer of surface finishing.


Die-cast parts have a satisfactory appearance and low surface roughness. But it’s not just about the looks and surface roughness of parts that are desired by people. Surface Finishing can also increase the corrosion and wear resistance of parts.


Surface finishes can protect your parts from the outside condition and has the ability to provide a die-cast part with electrical conductivity or insulating properties. That contributes to the durability and productivity of your parts.


So, it’s totally worth the extra cost to provide an additional surface finishing for your die-cast parts. But, if you are looking for the cheapest solution and don’t have very high standards, then you can skip the surface finishing.
What are the applications of Surface Finishing?

Surface Finishing is very important to ensure better quality and longevity of parts. The major industries dealing with metal parts will prefer a good surface finish to improve their product’s quality.


Surface Finishing can provide your parts with a decorative look and alter important chemical and physical properties. That’s why surface finishing has a wide range of applications in different industries and their products.


Wide range application of surface finishing can be seen in the following,


  • Automotive Parts
  • Medical Devices
  • Electronic Enclosures
  • Aerospace
  • Marine Industry
  • Robotics
  • Telecommunication
  • Defense etc.


The scope of use for surface finishing is basically endless. Any metal parts may be given a surface to make it more aesthetic or to protect it from harsh weather conditions.
What is surface roughness in Surface Finishing?

Surface Roughness is a measure of irregularity in the surface texture of metal parts. If the surface roughness of a part is more than a specified limit, then the surface is said to be rough. The surface is said to be smooth if surface roughness value is less.


Normally any surface is desired to have a smooth finish. One of the main functions of surface finishing is to reduce the surface roughness of metal parts. That can reduce the friction between metal parts and increase the performance of a machine.


Surface Roughness also has an impact on the durability of parts. Rough surfaces are more prone to wearing and tearing due to having a higher friction coefficient.


So, keeping the surface roughness value to the minimum is a basic requirement for any surface finishing. Although, that will have a significant impact on the cost of finishing.


There are instruments that can measure the surface roughness of metal parts. They are mainly used as a quality control measure for the finished parts.


What Surface Finishing are good for corrosion resistance?
Different type of Surface Finishing has a different purpose. So, not all of the surface finishing processes will ensure improved corrosion resistance. Some Surface Finishes that are good for resisting corrosion are discussed below.




Anodizing is a widely used surface finishing technique in the industry. It is an electrolytic passivation process that increases the oxide layer thickness of metal parts. Anodizing can increase the resistance to corrosion of metal parts.


Anodization is mainly used for Aluminum parts. It can reduce oxidation in adverse conditions. Although Anodization may not be so effective when dealing with salt, lime, and certain chemicals.


Powder coating


The process of powder coating has similarities with Anodizing. Both of them provide good protection against corrosion. But powder coating can ensure a better appearance in the parts.


It also has low toxicity and flammability. That makes it an ideal choice for the surface finishing of automotive parts. It is especially beneficial to steel parts as they are more prone to corrosion.


Chromate conversion coating


This surface finish works as a corrosion inhibitor that reduces the susceptibility to corrosion when metal parts come in contact with certain chemicals.


It also serves as a primer to improve the adhesion that allows coating with paint and other materials. The application of Chromate finish is often observed on hardware and power tools.


Liquid Painting


It is the most commonly used surface finish method.  It is very easy to apply and much cheaper when compared to other methods. It will provide moderate corrosion resistance and give your parts an aesthetic look.


Paints are not the most reliable coating. As it can be easily removed when glazed and also has high flammability. But it will definitely get the job done in an economical manner.
What is salt spray hours in Surface Finishing?


Salt Spray Hours is a unit of measurement used in the Salt Spray test. The test gives a relative measure of the corrosion resistance of a surface finish. But, the test can’t give an accurate measurement or correlation with the actual corrosion.


The test is conducted by keeping a metal part inside a salt solution to simulate an accelerated corrosion attack. The metal is left inside the testing equipment for a period of time. The time taken to corrode the part to a certain extent would give a value of Salt Spray Hours.


The value can be used to get some idea about the extent of corrosion resistance of a particular surface finish. It is possible to do so by comparing Salt Spray Hours of the test sample with a standard value.


However, this will only give a relative measure of the corrosion resistance of a surface finish. It can’t predict the real-world scenario of corrosion that normally takes years to happen.
Can Surface Finishing improve the thermal and electrical conductivity?
Yes, Surface Finishing can significantly improve the thermal and electrical conductive properties of a metal part.


One of the most ideal surface finish for improving conductivity is electroplating. It is a process where electric current is used to reduce metal cations from a solution that allows the formation of a thin coating on the metal part.


Electroplating can be done using several highly conductive materials such as Silver, Gold, Nickel, etc. In that case, electroplating may be termed as Silver Plating, Gold Plating, and Nickel Plating, respectively.


Nowadays, gold plating is widely used in electronic components. Because the conductive properties of a part are mostly needed in electronics.


Another fact is, both the thermal and electrical properties of a metal depends on the surface roughness of the parts to some extent. A greater surface roughness value can negatively impact the conductivity of a part.


Some Surface finishes also have shielding and insulating property. Such finishes are mostly applied to electronic enclosures for enhancing the performance of the product.


Here’s a link to a video that describes these facts in detail.


Does Surface Finishing increase the production cost?


Surface Finishing of any parts adds some additional steps to the manufacturing process. So, yes, it will increase the overall production cost of manufacturing. But, what’s important here is how much is that increase in cost?


Well, that depends a lot on your requirements. If you want your parts to have a nice texture with excellent material properties, then you will probably need a costlier solution for surface finishing. That can have a significant impact on the production cost.


So, you must be wondering whether it’s worth the extra money. A good Surface Finishing can greatly increase the durability of your parts and make them more attractive. So, you can ensure quality parts that will have a higher market value.


You can also choose some cheaper surface finishes for your parts if they aren’t subjected to any harsh conditions. This won’t have that much of a big impact on the overall production cost of the parts.


What Surface Finishing can be applied to Aluminum Die cast parts?


The type of finishes you can apply on a manufactured part depends on some parameters such as material, geometry, production method, etc. So, the material you used for production will have some influence on which type of surface finishes can be provided.


Normally Aluminum parts can be given the following type of surface treatments.


  • Anodizing
  • Grinding
  • Polishing
  • Powder Coating
  • Sand Blasting
  • Liquid Painting
  • Impregnation


Now, which one you need depends on the purpose of your parts. If you only need a decorative finish for your parts, then Painting, Powder Coating, Polishing, etc. would be enough.


But if you want to improve corrosion, wear resistance of the parts Chromate, Anodizing, Painting, etc. would be a better option.


Can multiple Surface Finishing be applied on a single part?


Yes, a single part may undergo multiple types of surface treatment processes. Based on the requirements for the final parts, often several layers of surface finishes are applied on a single part.


Suppose you want your parts to look nice and also have some special properties that will enhance your part’s productivity. But, each type of surface finishing has some specific function.


So, you may not achieve all of the desirable features with a single type of surface finish. Some Surface Finishes have a better appearance, some provide better protection and some balances between looks and protection.


If you want the best decorative finish and protection for your parts, you need multiple finishes for that. You can apply a protective layer of surface finish first, then apply another surface finishing that has a better appearance.
What is the process of Cleaning Surface Finishing?


Cleaning is an essential process that is mostly used as a preparatory step for surface finishing. If the manufactured parts already have a good finishing, then Cleaning can be considered as a primary surface finish as well.


Cleaning is a very important part of the finishing process that removes unwanted impurities from the surface of manufactured parts. It can be done by mechanical action or rinsing the parts in solvents.


Some of the advanced cleaning processes include,


  • Pressure Washing
  • Abrasive Blasting
  • Ultrasonic cleaning
  • Flame Cleaning
  • Steam Cleaning etc.


Each of the cleaning processes are done differently and have a different purpose as well. So, which cleaning process should be used depends on the quality requirements for the parts being manufactured.


Here’s a video showing Ultrasonic Cleaning of some manufactured parts.


What is the process of Anodizing Surface Finishing?


Anodizing is a surface finishing that uses the electrolytic passivation process. It works by increasing the thickness of the oxide layer on the surface of a part. The reason that it is called Anodizing is that the metal parts acts as an Anode in this process.


The Anodization process is discussed below step by step,



  • Firstly, the parts should be pretreated by glass bead blasting. It will remove the incomplete natural oxide layer and other impurities. It helps the anodic oxide layer to form easily.
  • Then clean the parts to wash away the residual abrasives that may be present after bead blasting of the parts.
  • Now, dip the parts inside a Sodium hydroxide solution and Sodium Carbonate solution to get a nice and clean surface.
  • Until now, these were all pretreatment processes. Now submerge the pretreated metal inside an Anodization chamber.
  • Rinse the parts once more after Anodization.
  • Then dip the anodized metal inside a sealing chamber. It will provide a coating over the parts to seal pores in the metal.


You can take a look at the video below that will help you visualize the process.


What is Chromate-Surtec 650 Surface Finishing?


Chromate conversion coating is a type of surface finishing used to passivate metal parts. It acts as a corrosion inhibitor and primer that enhances the adhering properties of paints and other coating materials.


Chromate Conversion has a nice decorative finish and improves the electrical conductivity of the metal parts as well. It will provide moderate corrosion resistance for metal parts.


Chromate-Surtec 650 is a type of Chromate conversion coating. It is a chromium (VI) free trivalent passivation for metal parts. The liquid concentrate Surtec 650 ensures excellent corrosion resistance that is on par with the corrosion protection of hexavalent passivation.


Surtec 650 is mainly used for coating Aluminum parts and as a pretreatment measure. Other surface finishes may be provided on top of a Surtec 650 finish.
How does Electroless Nickel Plating differ from Nickel Electroplating?


Electroless Nickel Plating is a surface finishing process that involves depositing an even layer of nickel or nickel alloy on the surface of a metal part. This process is done by submerging the parts to be plated inside a Nickel salt solution and reducing agent.


Nickel Electroplating also works by depositing a layer of Nickel on top of the metal parts. But, the major difference is that Nickel Electroplating uses electricity for the deposition process. Hence the distinction between the names of the two processes.


Both of the methods have their pros and cons. But Electroless Nickel Plating is comparatively cheaper than Nickel Electroplating. Because Nickel Electroplating needs some additional steps to be completed before it can be plated.


Nickel Electroplating is sensitive to impurities. In order to proceed with this technique, the parts may be required to go through some processes such as blasting, cleaning, heat treating before the plating process can begin.


Electroless Nickel Plating, on the other hand, uses a reducing agent for deposition and is not too sensitive like Nickel Electroplating. That ensures a uniform deposition of coating along the entire surface.
What is the difference between Powder coating and Liquid Painting?


Powder coating is a free-flowing type painting, unlike any conventional liquid painting. It is delivered electrostatically and cured under heat or ultraviolet rays. This powder can be a thermoplastic or a thermoset polymer.


Liquid painting is a conventional way to paint, which is delivered via an evaporating solvent. After applying a thin layer on a substrate, the liquid turns into a solid film. Most of the paints are either oil-based or water-based.


Which one is better totally depends on the kind of application. But powder coating is better in terms of durable protective finish on your metal object. Due to the electrostatic process, powder coats are more efficient.


Powder coating cost is slightly higher than liquid painting. But you can apply it fast, and it is also eco-friendly. On the other hand, liquid paints produce more waste, but its color can be rendered in a broader range.
What is the difference between Shot Blasting and Sand Blasting?


Shot Blasting is a process where the impurities present in the part’s surface is removed by using an abrasive. It is a technological process and used as surface protection.


Sand Blasting is the process of propelling abrasive media with compressed air. This procedure takes compressed air as a power source and directs a high-pressure stream of abrasive on the surface.


The main difference between Shot and Sand Blasting is that the first process we use throwing wheel and the second one is done by using compressed air. But both of the processes make use of abrasive.


Whether Shot Blasting or Sand Blasting is required somewhat depends on the field application of the parts. Thick and heavy surfaces will be quickly prepared by Shot Blasting, and the other may take slightly more time.


What is the difference between Anodizing and E-coating?


Anodizing is used to increase the thickness of the natural oxide layer on metal surfaces. It’s an electrolytic passivation process. It improves the adhesion for paint primers and improves resistance to corrosion.


E-coating is also known as Electrostatic Coating. It is a manufacturing process that is done by dipping electrically conductive parts into a tank of paint. Anodizing also involves a similar process where the parts are dipped inside a solution for Anodization.


Anodizing is an oxide layer when E-coating is a thin coating that protects a surface. The first one is mostly applied to aluminum, while the other one can be used on any conductive metal.


Anodizing is comparatively cheaper than E-coating, but colored anodize does not do well under UV exposure. But E-Coating has an excellent exterior UV protection as Urethane.


What is the difference between Silk Screening and Pad Screening?


Silk Screening, also known as Silk Printing, is a type of screening process that utilizes silk. It is done by using a mesh to transfer ink onto a substrate by a blocking stencil. Different types of mesh sizes are used to determine the outcome of the material as per the design.


Pad Screening is quite a modern process. Like its name, the item you want to print transfer ink from a silicone pad. The machine holds both the product and the pad steady. Then it presses the pad into an ink plate, which gives the shape of your artwork. Then it is left to air dry.


During your artwork, this should not be your concern about which one is better. What you need to know is which one is better for your product. When pad printing is ideal for small products, there silk printing is better for bigger products. Also, the pad is fast, and silk takes a bit more time.


For unusual shapes, pad printing can be the best choice. Also, it can use in 3D shapes or uneven areas. But silk printing can be a bit hard on those areas. But keep in mind that pad printing is cheaper compared to silk printing.


What is the process of Laser carving Surface Finishing?


Laser Carving, also known as Laser Engraving, is a method of engraving an object using lasers. This process is used as a surface finishing method for metal parts. It is usually used for marking texts and logos in a metal part.


Laser carving can precisely carve any images on the surface of metal parts. This is mostly used for marking the numerous metal parts that are being produced. This is also used for carving the manufacturer’s logo in metal parts.


Laser engraving has become more popular than before, and manufacturers are finding innovative use for this process. Laser Engraving has been successfully used for providing an accurate surface finish to metal parts.


Laser Carving is a very simple process without any sort of complication. It is a computer-operated process and has very little chance of errors. There is not much manual process involved in laser engraving.
What Surface Finishes are good for automotive parts?

The automotive industry keeps growing day by day without showing any signs of stopping. So, the manufacturers must ensure the best quality to the consumers to survive in this highly competitive industry.


Surface Finish is a major part of the manufacturing process of automotive parts. A good surface finishing can ensure better performance of the parts for a longer period.


Let’s have a look at the type of surface finishes that are good for automotive parts,


  • Anodizing
  • Cleaning
  • Shot peening
  • Sand Blasting
  • Electroless Plating
  • Powder Coating
  • Electroplating


These are some ideal surface finishing choices. Which one to use depends on the type of parts, application, and, most importantly, cost. And a single part may require multiple surface finishing, where one provides protection, and another enhances the outlook.


What Surface Finishes are good for electronics parts?

Consumer Electronics have become very popular lately. We can easily notice the excessive demand for electronic goods nowadays. And there is mind-boggling competition among the manufacturers.


So, ensuring better quality and durability for electronics parts has no other alternative. A proper finish can significantly contribute to this matter. Unlike other parts, electronic parts often need some special properties as well, which is achieved by certain surface finishing.


Some Surface Finishing important for electronic parts are mentioned below,


  • Electroplating (e.g., Gold Plating, Silver Plating, etc.)
  • Anodizing
  • Conductive Coating


The main scope of the application of surface finishes in electronics is the enclosures. Based on the requirement, a conductive coating or electrical and thermal resistive coating can greatly contribute to the performance of the electronics as a whole.

Do you have QA Test equipment for Surface Finishing?


Sunrise Metal has the latest QA test equipment to ensure superior quality for the surface finishing of your parts. Some of the quality control equipment and their application are discussed below.


Salt Spray Testing Equipment


Salt Spray Testers are used to create a controlled environment to estimate the probable corrosion resistance of parts and surface finishes. However, this does not give an accurate measure of the corrosion resistance of any coatings.


This is a test to evaluate the suitability of certain Surface Finishes such as Painting, Anodizing, Electroplating, etc. It gives fairly good results to assume the expected corrosion resistance of these finishes. And it is relatively inexpensive as well.



Thickness Testing Machine


Thickness Testers are non-invasive ultrasonic instruments that are used to measure the thickness of surface finishing provided on a metal part. It ensures that a certain coating is uniformly spread along the entire body of the metal.


This instrument can be used on both ferrous and non-ferrous to measure the thickness of coatings on them. But the working principle is different. It is done by either magnetic induction or eddy current measurement.



Color Meter


Color Meter is used to identify the color and measure the luminescence of the surface of a surface. Color Meter can be used on both a solid and liquid surface.


The data obtained from the color meter is useful to estimate the accuracy and consistency of the color of the surface finish. So, you can expect to get color-accurate parts with great aesthetics.



What are your Surface Finishing capabilities?


Once the tooling, casting, and machining of your parts are done, we can apply aesthetic and protective coatings for you. We have in-house surface finishing facilities to provide you the basic type of finishes such as,


  • Cleaning
  • Tumbling
  • Shot blasting etc.


But that’s not all, we have partnered with other companies that specialize in advanced surface finishes. So we can provide you with various other types of surface finishes as well such as,


  • Liquid Painting
  • Powder Coating
  • Chromate
  • Anodize
  • Electroless Nickel
  • Silk Screening
  • Pad Screening
  • Laser carving, etc.


We have handled numerous surface finishing jobs until now. Take a look at some of our previously completed surface finishes.



Why should I choose sunrise for Surface Finishing?


Sunrise metal has advanced Die Casting and CNC machining facilities to manufacture quality parts with excellent strength and tolerance. And we offer various Surface Finishing in order to ensure better performance and longevity of your parts.


Take a look at what makes us a better choice when it comes to surface finishing.


Wide range of finishing


We have in house Cleaning, Shot Blasting services, We are partners with experienced companies who specializes in surface finishing.  That allows us to allow us to offer various types of surface treatments.


Some of them worth mentioning are Liquid Painting, Powder Coating, Chromate, Anodization, Electroless Nickel, Silk Screening, Pad Screening, Laser carving, etc.


Strict Quality Control

We have organized management and experienced employees who are dedicated to the quality control of your products. We have advanced quality control tests for your surface finishes as well.


One-Stop Solution
Manufacturing anything is a complicated process and involves a lot of steps. Going door to door for different processes will cause you a lot of hassle and unnecessary delay. We provide all sorts of manufacturing services.


So, you can count on us for design, tooling, and die casting of your parts. Once that’s done, we can apply aesthetic, and high-quality surface finishes for you.


ROHS & REACH Compliance
RoHS and REACH are legislations that restricts the use of certain hazardous materials. All of our surface finishing processes are compliant with RoHS vs. REACH. We do not make use of any hazardous materials that may be harmful to the environment.


10+ years of experience

We are an experienced manufacturing company with over ten years of experience in this field. Our vast knowledge and experience allow us to provide you better suggestions and ensure the best quality with the least money spent.


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