Polishing Stone
There are various types of molds, such as press molds, die-cast molds, and plastic molds, and the final step in the mold manufacturing process is the polishing process.
In recent years, the development of machining accuracy has made it possible to produce high-quality mold products without the polishing process, but the number of products requiring high precision and high quality has increased, and the polishing process cannot be omitted.
Product Details
▼ Mold Manufacturing Process
Molds are created by shaping with milling and electrical discharge machining, refining shapes with files and mounted grinding stones, removing surface scratches and unevenness with coarse-grit stick stones (mold stones), and gradually increasing the grit size for polishing.
▼ Importance of Plastic Mold Polishing
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① The roughness of the polished surface is directly transferred to molded products.
When resin is poured into a mold for shaping, the mold's shape and surface roughness are directly reflected on the plastic product, making this a critical task.
In recent years, products requiring mirror finishes have increased, leading to the use of fine-grit stones for pre-polishing with diamond paste. -
② Reduces resistance during resin flow and product demolding.
After molding, when resin is poured into the mold, cooled, and removed, unpolished surfaces cause poor resin flow, trapping air bubbles and leading to product defects.
Additionally, poor demolding due to rough surfaces increases production costs. -
③ Enhances the appearance and value of molded products.
As mentioned in ①, the mold's surface condition is directly transferred to the product, affecting gloss, light reflection, and color.
Thus, high-value plastic products with a glossy, mirror-like finish require molds polished to perfection.
▼ Selecting Mold Stones
For general grinding stone selection, the combination of abrasive type, grit size, and bonding is crucial. However, for mold stones, resin treatment and grit size significantly affect usability. Mold stones treated with resin use WA abrasives.
The bonding depends on the product and processing method.
▼ Grinding Oil
We offer a specialized oil for mold stones, "BLUE CUT YS-601."
Product List
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WA
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These are ceramic grinding stones using WA abrasive grains, which are the most common type. They have excellent friability and generate less heat, making them suitable for grinding operations with large contact areas between the workpiece and the stone, as well as for finishing and light grinding of high-speed steel and special steels. |
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C
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These are ceramic grinding stones using C abrasive grains. They are more durable than WA stones and are suitable for grinding castings and press molds. Available in grit sizes up to #2000. |
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GC
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These are ceramic grinding stones using GC abrasive grains, which have the highest hardness among abrasives. They generate minimal heat, making them ideal for grinding materials sensitive to heat. They are suitable for precision grinding of hard materials such as carbide tools and superalloys. |
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YHZ (BLUE IMPULSE)
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These ceramic grinding stones are developed for intermediate and finishing applications. While they wear slightly, they demonstrate exceptional grinding performance. They are all-rounders that can adapt to various mold steel materials in both dry and wet conditions. Compatible with both oil-based and water-soluble oils, they are environmentally friendly and free from substances harmful to humans and the environment. The stones come in two hardness levels: “L” (hard) and “J” (soft). |
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YHA
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These are ceramic grinding stones with melamine resin added to WA stones, combining the advantages of WA stones with improved wear resistance. They maintain good adhesion and appropriate resin strength, providing balanced grinding performance and minimal shedding. They excel at removing altered layers from hardened and EDM-treated materials and are also effective for rough to intermediate finishing of carbon and tool steels. The stones are available in one hardness level: “I.” |
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YHB
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These are ceramic grinding stones impregnated with general-purpose phenolic resin for rough to intermediate finishing. With high resin strength, they are resistant to breaking under heavy loads, such as rib grinding or grinding rough surfaces. They are suitable for dry use. The stones are available in one hardness level: “I.” |
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YHB-T
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These are ceramic grinding stones impregnated with high-fracturing phenolic resin for rough to intermediate finishing and are the strongest in the YH series. They are effective for removing altered layers from machined or EDM-treated materials and for achieving uniform surface finishes where roughness is critical. The stones are available in three hardness levels: “L” (hard), “J” (medium), and “H” (soft). |
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YHF
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These grinding stones use GC abrasive grains bonded with phenolic resin. They are highly elastic and less prone to causing scratches, providing uniform finishes. They are suitable for finishing hardened steel and tool steel, where surface and shape precision are required. The stones are available in one hardness level: “K.” |
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YHS
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These are grinding stones impregnated with sulfur to prevent grinding marks on molds. The sulfur provides lubrication, improving surface roughness and reducing wear. The stones are available in one hardness level: “I.” (Caution) As a flammable solid, always air-dry these stones naturally. Forced drying can cause fires. |
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YTM
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These resin-based grinding stones are developed for final finishing and mirror polishing of molds. They provide excellent gloss due to their soft touch and moderate strength (similar to wood). They are ideal for corners and grooves that are difficult to polish with paper and achieve over five times the gloss of ceramic stones. The stones are available in two hardness levels: hard and soft. (Caution) As a flammable solid, always air-dry these stones naturally. Forced drying can cause fires. |
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PA
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These are ceramic grinding stones using PA (Pink Alumina) abrasive grains. ● Grit Sizes |
▼ Standard Stock (Grit Sizes) ※Excluding PA and YTM
| #80 |
#100 |
#120 | #150 | #180 | #220 | #240 | #280 | #320 |
| #400 | #600 | #800 | #1000 | #1200 | #1500 | #2000 | #3000 |
▼ Standard Stock (Dimensions) ※Excluding PA
| 100×6×3 | 100×13×3 | 100×13×5 | |
| 150×6×3 | 150×13×3 | 150×13×5 | 150×13×6 |
