Sandblasting

Since the founding of our company, our engagement in Sandblasting has led to significant accomplishments.

Sandblasting plays a crucial role in post-treatment processes and is effective in cleaning residues from parts after heat treatment, such as oxidised skin, residual salts, and similar contaminants. It also serves to strengthen the surface of components, thereby enhancing their fatigue strength. Additionally, sandblasting is beneficial for rectifying issues in thin, elongated parts as well as correcting deformations in thin-walled components.

For advice or more information call us today on +44(0)1827 712910 or email us at sales@coler.co.uk

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Understanding Sandblasting at Coler Supply Solutions

Sandblasting, also known as abrasive blasting, is a versatile technique employed in various industries to prepare or finish surfaces. The process involves propelling fine particles, typically sand, at a high velocity towards a target surface. This forceful action effectively removes impurities such as dirt, rust, and flaking paint, resulting in a clean and even surface.

The principle behind sandblasting is using a high-pressure hose, with the key difference being the use of abrasive materials instead of water. These abrasive particles are capable of stripping away tough, unwanted coatings and contaminants, leaving the surface beneath intact and smooth. This makes sandblasting an ideal preparation step before applying new paint or other treatments, as it ensures better adhesion and a more polished finish.

Sandblasting is widely used on metal surfaces, making it a popular choice in automotive, shipbuilding, and manufacturing industries for cleaning and refurbishing car parts, machinery, and structural components. Its efficacy in removing rust and old paint without damaging the underlying material makes it a preferred method for restoring old vehicles or equipment.

Effective Sandblasting
with Coler Supply Solutions

Sandblasting operates through compressed air to swiftly create a jet stream, spraying materials (like ceramic sand, glass beads, nylon sand, quartz sand, emery, and iron sand) onto the surface of parts that require treatment. This process effectively shapes and textures the exterior surface. The impact and grinding action of the abrasive material on the part’s surface not only enhances the fatigue strength of the parts but also improves the adhesive bond between coatings, thereby boosting durability. This makes it ideal for leveling and decorative purposes.

Prior to coating, sandblasting efficiently removes all grease from the surface and creates a crucial base layer, often referred to as a matte side. It can adjust the bond strength between coatings and the surface by varying the granularity and roughness of the abrasive material, thus enhancing the adherence and overall quality of the finish.

Sandblasting is also instrumental in treating the surfaces of castings, cleaning parts post-heat treatment, and polishing. It effectively removes all surface contaminants like oxidized skin and grease, resulting in a uniform metal color that elevates the part’s aesthetic appeal.

Coler Supply Solutions offers a rapid and efficient sandblasting service, catering to a range of requirements.

Additionally, sandblasting is effective in removing burrs from parts, thereby enhancing their completeness and quality while mitigating risks associated with burrs. It can also subtly angle the junction area of two surfaces to improve the part’s aesthetic value.

The process also significantly improves the mechanical performance of parts. Post-sandblasting, parts exhibit a uniform and finely uneven surface that can retain lubricating oil, thereby enhancing lubrication, reducing noise, and extending service life.

Furthermore, sandblasting can achieve various gloss effects for specific applications. It enables different reflective or matte finishes, applicable to a wide array of materials and products like stainless steel parts, plastic rubber grinding, jade polishing, wooden furniture surface matting, pattern creation on matte-effect glass, texturing of fabric surfaces, and more.

Pretreatment Stage

The pretreatment phase of sandblasting refers to the necessary treatment of a component's surface prior to spray painting and electroplating.

The standard of sandblasting influences the adhesive strength, aesthetic appeal, moisture resistance, and corrosion resistance of the coating. Insufficient pretreatment may lead to erosion spreading beneath the coating, resulting in its detachment. In comparison to surfaces treated with various coatings and exposed to prolonged sunlight, those that undergo thorough treatment and cleaning can have a service life 4-5 times longer. Various methods exist for surface cleaning, with solvent cleaning, pickling, and the use of hand or power tools being the most effective.

Sandblasting is highly effective in applying abrasive jets. There are two primary types of sandblasting machines: dry and wet. Dry sandblasting machines can be further divided into suction and pressure blasting.

The abrasive materials utilised in dry blasting include steel sand, alumina, quartz sand, and silicon carbide. Dry blasting processes can involve mechanical or air pressure blasting.

Sandblasting Applications

Sandblasting is extensively employed across various industrial sectors, including mechanical engineering, automotive components, metal casings, glass, hardware, and electronic products. While it is particularly useful for precise parts and those with special requirements, it serves adequately for many standard applications. This treatment is crucial in preparing surfaces for painting, electroplating, oxidization, and phosphatizing processes. In sandblasting, quartz sand is commonly used.

The choice of sand size and air force depends on the characteristics of the materials and parts being treated. It is imperative to promptly apply surface treatment to parts post-sandblasting. If immediate treatment isn't possible, temporary protective measures, such as immersion in steel carbonate or sodium nitrite solutions, should be employed. Furthermore, parts requiring hard chromium plating must undergo sandblasting, and this is also applicable to electroplated milky white chromium. Blasting prior to electroplating enhances the adhesion between the electroplating layers and the base material.

Achieving a satisfactory blasting effect relies on the use of dry sand and a dry matrix material surface. The pressure of compressed air is directly linked to the sandblasting process. For softer materials or thin-walled parts, a lower air pressure is advisable, whereas higher pressures are necessary for other materials to ensure the effectiveness of blasting and to prevent damage to the abrasive material.

In the casting industry, sandblasting not only strengthens castings but also serves other purposes, like dealing with castings, burrs, and sand treatments, making it a staple in metal casting.

The hardware industry utilizes sandblasting for a range of products, including stainless steel items, containers, aluminum materials, copper products, belt rings, automotive metal shells, the watch industry, and the workpiece strengthening wire drawing.

In the electronic industry, it's used for surface blasting treatment and plate sanding and wire drawing treatments for precision instrument parts.

The building material industry also benefits from sandblasting for materials like plastic rubber, glass, and porcelain. For instance, some matte glass with unique patterns is a result of sandblasting.

Mastering the Art of Sand Blasting Surface Treatment:

1. Verify operational conditions such as nozzle functionality, lighting, ventilation, compressed air supply, and any sand leakage. Address any identified issues promptly to ensure smooth operations.

2. Confirm alignment of the parts list with actual components to avoid errors. Count the number of parts and immediately report any discrepancies for resolution.

3. Thoroughly inspect each part for damages like dents, scratches, cracks, or other defects. Proceed with sandblasting only after receiving clearance from the relevant personnel.

4. Assess the need for protective measures on certain parts and apply them as necessary.

5. Ensure all protective gear, including masks, rubber gloves, protective clothing, and safety helmets, is worn.

6. Check the air equipment pressure prior to sandblasting, ensuring the compressed air pressure is between 3 to 5 atmospheres.

7. Turn on the headlamp, open the compressed air valve, and allow the nozzle to run empty for 2 to 5 minutes to clear any moisture in the pipes and prevent sand dampening. Then, close the valve and insert the sand delivery pipe into the sand.

8. Place the parts inside the work chamber and securely close the door.

9. Start the ventilation system and open the compressed air valve to begin sandblasting. Maintain the nozzle at a 30-40 degree angle, rotating and flipping the parts evenly for a uniform spray, until the surface achieves a consistent silver-grey appearance. For smaller parts, continue until the desired sandblasting effect is achieved.

10. Parts requiring precise cleanliness or accuracy should not be sandblasted locally until after protective measures are applied.

11. After completing a batch of parts, promptly close the compressed air valve and remove the parts.

12. Following sandblasting, immediately proceed with the next stage of the process, which may include anti-rust treatment. For parts not receiving matte chrome plating, proceed directly to electroplating.

13. Iron castings that have been sandblasted and roughened should be transferred to the machining workshop without anti-rust treatment.

14. Conduct sandblasting in a designated machine using new, dry sand free of impurities.

15. Use silica sand with a particle size of 0.5 to 1mm (number 20-40) for sandblasting, with compressed air pressure set between 0.3 to 0.66 Mpa (2-6kg/cm2).

16. For precise parts, measuring tools, cutting tools, or parts with low hardness, use lower pressure and increase the nozzle-to-part distance to ensure quality. For ordinary or sturdier parts, use higher air pressure and maintain an appropriate distance.

17. Angle the nozzle between 30 and 40 degrees during spraying, avoiding direct vertical spraying.

18. Rotate and adjust the nozzles and parts for even coverage, achieving a uniform silver-grey surface, while avoiding prolonged spraying that could damage the parts due to high pressure.

19. Apply protective measures to areas of parts that should not be sandblasted.

20. When blasting spring collects, check for sand blockages in holes and avoid blasting in areas with holes smaller than 1mm.

21. During sandblasting, report any discovered cracks, dents, or other quality issues immediately for prompt resolution.

22. To prevent injuries, operators must consistently wear protective gear throughout the operation.

Understanding Control

Understanding Pre Control

Ensure thorough inspection and removal of welding slag, spatter, and any adherent materials, followed by cleaning off surface grease and soluble contaminants. Any unnecessary welding joints or connections should be addressed and dealt with appropriately.

The sand employed in sandblasting for rust removal needs to be hard, sharp-edged, and dry (with a water content of less than 2%), free from mud and other impurities. Quartz sand and emery are ideal choices, with the particle size ranging between 0.5 and 1.5mm. Ensure the sand is completely dry before it is sieved, and store it in a dry indoor area. For sieving, use a screen with 40-48 holes per cm² (for 1.2mm particle size) and a finer screen of 372 to 476 holes per cm² (for 0.3mm particle size).

Tool Control:
When conducting sand blasting operations, the air pressure of the air compressor should be maintained between 6.0×10⁵ and 6.5×10⁵ Pascals, with a pressure variation range of 0.5×10⁵ to 1.0×10⁵ Pascals.

Understanding Quality Control

Upon completion of sandblasting, the operator must conduct a thorough inspection of the de-rusted areas. This includes checking the cleanliness and roughness of the underlying steel surface, with particular attention to areas that are challenging to spray. The standards for rust removal via manual or power tools may be moderately relaxed. It is important to avoid touching the surfaces with hands. The sandblasting process should be carried out in diffused sunlight or under artificial lighting with equivalent brightness to prevent any oversight during inspection. After sandblasting and rust removal, the surface cleanliness of the metal structure should meet the Sa2½ standard, and the surface roughness should be between Ry60 and 100 micrometres. Corresponding roughness samples should be used for comparison, as per the technical specifications.

Common Questions

Why Choose Coler Supply Solutions?

To ensure that your manufacturing plan operates efficiently and with the flexibility required to maintain high-quality standards, it's crucial to implement strict project flow management. Here's a concise guide to achieving this:

Product DFM Analysis

Mould Design

Mould Making

Mould Trial

Sample Approved

Large Volume Production

Quality Control

Packing

Delivery

Customer Aftercare