Coin Mint Line

gold bullion
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  • Why to mint gold coin:


Gold is an excellent hedge product. When the world political situation and economic instability, especially in the event of war or economic crisis, all kinds of common investment tools will be seriously impacted, such as stocks, funds, real estate and so on. At this time, gold reflects a good risk aversion attribute. Even in the face of economic crisis, the price of gold can remain unchanged or even rise steadily, maintaining the value of assets. So usually precious metals will be made into jewelry, gold bars and gold coins in the market.


  • Advantages of gold:


(1) Safety: gold is recognized as the best hedging product in the world.

(2) Liquidity: the gold market has 24-hour trading, with many profit opportunities, loose trading time and convenient trading mode, which does not conflict with working time and place; investors are allowed to conduct multiple transactions; therefore, it can be changed into banknotes at any time.

(3) Reverse: when paper money fluctuates and depreciates due to credit crisis, gold will appreciate.

(4) Rarity: the earth’s gold stock is limited, but the demand is rising in a straight line!

(5) Investment: due to the long-term upward trend of gold, and the gold market can not be manipulated artificially, the risk is small, suitable for medium and long-term investment.

  • How to Mint a Fine Gold Coin:


*Chapter I – Introduction to coins

1.1. Development

1.2 Type


*Chapter II – The Production Process of Bullion

2.1 Step 1: Bullion casting

2.2 Step 2: Hydraulic logo stamping


*Chapter III – The Production Process of Coin

3.1 Step 1: Silver/Gold strip casting

3.2 Step 2 .Rolling mill treatment of gold bar surfaces

3.3 Step 3: Obtaining Coin Blank

3.4 Embossing


*Chapter IV – Guide purchase of minting machine


*Chapter V – Conclusion



gold coin casting line1

*Chapter I – Introduction to coins

As a metal currency, gold is not only an important financial asset, but also an effective tool to avoid the risks of economic recession and inflation. Gold’s hedging function is hard to be replaced by other currencies.



In ancient times, gold coins were mainly used as the medium of exchange and assumed the function of circulation. Therefore, the ancient gold coin is the most valuable unit of its weight, known as the weighing currency, the value of which is equivalent to the weight of gold. In essence, gold is eternal, the most stable of all metals and the least prone to chemical reactions. It does not rust, discolor, or corrode. Due to its durability, density and glittering features, gold naturally becomes a symbol of wealth. Additionally, gold is so malleable that you can turn it into any shape you want. It is precisely because gold has so many suitable attributes as currency that human beings choose gold as currency in the free economy.

With the development of commodity exchange and the continuous evolution of currency forms, the weighing currency is transferred to metal coins, and the face value and market value of gold coins are gradually separated. Before the 20th century, gold coins played an important role as a means of payment and circulation. After the 20th century, with the further development of the society, the paper money is widely used in the world to replace the gold and silver money in circulation. The function of the means of payment and circulation of the gold and silver money has greatly declined. By the end of 1970s, after the non monetization of gold, the gold coin had no function of medium exchange. Today, gold coins mainly evolved into commemorative and investment currencies for collection and investment.


gold coin


At present, gold coins participating in transactions in the international gold market are mainly divided into four categories: circulating gold coins, trading gold coins, pure gold coins and commemorative gold coins.


1. Pure gold coin


The so-called pure gold coin is issued by the central governments or banks of all countries in the world. In order to meet the needs of ordinary investors who want to have coin like gold for gold storage, it is forged into a currency with certain weight, color, face value and shape. Pure gold investment, just like gold bar investment, is a good and safe way to maintain the value of investment.

Since ancient times, there have been countless types of gold coins that have been cast and issued worldwide. At present, there are more than ten kinds of gold coins that are relatively common in the world gold market.

(1) South African fuglin gold coin;

(2) Canadian maple leaf gold coin;

(3) Mexican free gold coin;

(4) British gold coin;

(5) American Eagle ocean gold coin;

(6) Austrian gold coin;

(7) Colombian gold coin;

(8) Australian kangaroo Hongyun gold coin;

(9) Singapore lion gold coin;

(10) Chinese Panda Gold Coin


2. Circulating gold coin


Circulating gold coin is issued by some countries for circulation purpose. In history, almost every ancient civilized country has used precious metals such as gold, silver and so on as coinage materials in its currency evolution and development process. Additionally, the currency value is expressed and determined by the weight of gold and silver.

The early gold coins were mostly produced by hammering, but they were also legal currency. Generally speaking, after the first World War, the circulating gold coins gradually withdrew from the circulation field and became the object of people’s collection. But it is not absolute, because until now, there are still a small number of gold coins circulating in the markets of India, Bangladesh, Myanmar, Thailand, Laos, Cambodia and some countries in the Middle East and West Africa in South Asia and Southeast Asia.


3. Commemorative gold coin


Commemorative gold coin is issued by central governments or banks around the world in limited quantities for a certain commemorative subject matter, being forged into a currency with certain weight, color, face value and shape. It has a long history to issue commemorative gold coins in the world.

The investors of commemorative gold coin and pure gold coin have different investment purposes, investment methods and techniques. Compared with pure gold coin, the investors of commemorative gold coin own richer money knowledge, higher art appreciation level and greater coin appreciation ability. Therefore, commemorative gold coins are generally only traded in specific transaction venue, and are circulated among coin collectors and enthusiasts.


4. Trade gold (silver) currency


The trade gold (silver) coin refers to the gold coin (also known as hard currency) specially used for the means of payment in international trade, which was mainly circulated in the colonial countries and regions occupied by Western powers during the period of 1850-1940. The trade gold coin originated from the merchant of Venice in the middle ages of Europe. Trade gold coin can have face value and weight, but it is more emphasized that its actual content is expensive. Gold coins exiting the trade field will have different prices depending on the quality and age. In many occasions, circulating gold coins and pure gold coins can also be used as means of payment in international trade.

*Chapter II – The Production Process of  Gold /Silver Bullion Casting




The bullion and coin supplier will engraving logo or pattern on the gold for sale. This Chapter will help you know more about the bullion casting and logo stamping process.


2.1 Step 1: Bullion casting


 Vacuum gold/silver bullion casting machine 


Before stamping logo, you need to make a shining bullion. With the development of the technology, one vacuum bullion casting machine can help you obtain the gold ingot with mirror effect directly. You just need to put the pre weighed gold/silver grains or powder into our custom-designed graphite mould, and then positioned inside the Vacuum melting chamber.  Close the door of the melting chamber, press the START switch to release the automatic cycle,  and the casting will started automatically. After finished the casting cycle, you can obtain the gold or silver bar which is ready for the market.


During the whole casting process, the whole melting and cooling down process will takes place in a closed chamber , we have design a automatic program which can vacuum the melting chamber automatic, you just press the bottom of vacuum , the vacuum process will be automatic done within 5 minutes, what is more, inert gas like Argon or Nitrogen will be filled in the melting chamber which can prevent the silver or gold from Oxidation.

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gold bar
gold bar making machine

The features and advantages of the bullion casting machine:


1. Vacuum atmosphere. The surface of the gold bar is smooth, non-porous almost negligible loss and with mirror effect after using full vacuum melting one time rapidly molding.

2. PLC control. The use of fully automated control can be achieved more than ordinary workers, greatly saving production costs, is the major precious metal refinery necessary machine.

3. With alarming system. Overvoltage, overcurrent, shortage of water supply and any other problem can be detected easily and sound alarm to notice.

4. Energy efficient, higher power factor and power efficiency.

5. Environment protection. The process of the line is smokeless. The machine is equipped with the latest green technology in the gold bar industry.

6. 100% full load and 24 hours consecutive working

7. Flexible working modes of constant output voltage or constant current / constant power.It has been solving the phenomenon like contraction, water waves, oxidation and unevenness.



Instructions for manual operation of the bullion casting machine:


1. First, push the (automatic, manual) button to manual mode.

2. Load the product into graphite mold and put it into the cooling plate, the mold can be customized based on customer’s need, for the size or the shape.

3. After closing the working cylinder cover, press the “Close the lid” button, then press the “cooling plate fall” button to descend to the heating area, press the “vacuumizing” button to start vacuum about (3-4 minutes),at the same time press “heating open” button, start heating. Power is usually adjusted to the maximum.

4. After heating for about 7-8 minutes, press the “cooling plate rising” button, the cooling plate will automatically rise to the lower part of the graphite mold to cool, at the same time, press the “shielding gas” button to add protective gas.

5. After finishing cooling, press the “Exhaust” button, open the cylinder cover and take out the graphite mould.



Instructions for automatic operation of the bullion casting machine:


1. Adjust the parameters of vacuum time, heating time, cooling time and alarm time.

2. First, push the (automatic, manual) button to automatic mode.

3. Load the product into graphite mold and put it into the cooling plate. The mold can be customized based on customer’s need, for the size or the shape.

4. Close the cylinder cover and press the “Automatic start” button, automatic mode startup.

5. When the setting time is complete, the machine alarm will automatically remind.

6. Open the cylinder cover and take out the graphite mold.


The end product:

The bullion comes out finally will be smooth, lustrous, with mirror effect. If you pursue perfect condition, you can use the the polish machine to make it more shiny. Then you can prepare to stamp the logo or the pattern you want on the bullion.

2.2 Step 2: Hydraulic logo stamping


To do a bullion logo stamping, you must need a hydraulic press machine. CDOCAST hydraulic press machine is technically designed to match the complete gold ingot production line. Through the hydraulic pump as the power source, the stamping is completed by the force of the pump. It can be used for different size of bullion with the mould which would be customized based on customer’s requirement.


Instruction for operation:


1. Start the machine

2. Put the bullion inside the opened cubicle

3. Put the customized mold on the bullion

4. Swing beside device and press the logo

5. The gold is soft, but you may still need dozens or hundreds of tons of presses to stamp the wanted pattern and logo. To make the best solution, we still need to know some information from your side.

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1.The raw materials you use is genuine gold or counterfeit gold material. The purity of the gold… it may affect the quality of the end product.

2.The shape of the bullion you want to cast. We can customize the mold based on your requirement.

3.The pattern or the logo you want to cast. You can offer us with 3D drawing, so that we can decide how many tons of the presses for the hydraulic machine is most suitable for you.

*Chapter III – The Production Process of Coin

This chapter will introduce you the whole process of the coin minting production, from melting raw material to embossing the gold coin. The end product can be sold in the market directly.

Silver coins are usually made of pure silver with purity of 99.9%, and 92.5% and 90% are the most widely used in the world. Gold coins are usually made of 99.99%, 99.9% gold and silver or gold copper alloy.


3.1 Coin casting:

As a professional and experienced silver/gold coin-minting line supplier, CDOCAST can meet all requirements of the buyer for coin minting, such as shape, thickness, pattern and so on.

In this process, the production will be divided into three processes. We will make the raw materials into the bars at first, and then roll them to the thickness we need. Last, punch.


Step 1: Silver/Gold  strip  casting


Continuous casting machine for gold/silver strip casting


Unlike bullion casting, this step we will use continuous casting machine to make gold/silver strip as per requirement. for example, if we want to do coin with diameter of 60mm, and 5 thickness, we will cast a 60mm width, and 6mm thickness(consider 1mm for the rolling mill reduction in thickness).

Put gold or silver  into the graphite crucible of the continuous casting machine .The metal will be melted in the crucible, and then the gold/silver strip of the desired specification will be cast on the assembly line.

CDOCAST continuous casting machine is suitable for casting K gold, gold, silver and copper. It mainly adopts the mixing function of American original intermediate frequency movement, which is in the leading level in the world and fully automatic control (no manual). Easy to understand operation, perfect protection function, prevent wrong operation. Full time gas (argon, nitrogen) protection. Reduce loss, PID intelligent temperature control.

The machine adopt the high temperature circulating cooling pulling design, also inside have the pulse stir device for keeping the same metal percentage of all. according with different mould, the machine can produce  Special shaping precious metal like gold, K gold, sheet pulls of silver, Tuble Pull, Bracing wire pull etc. The machine have equipped with the argon gas protection device for guarantee not oxidation and loss.


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upward casting machine
Continuous casting machine

The features and advantages of the continuous casting machine:


1. Graphite crucible & Induction Technology based heating system which can guarantee 24-hour Continuously Working.

2. High-tech cooler as well as graphite casting die tooling design which can custom-made for types of shapes.

3. Accurate control of withdrawal extraction pulse activity which can produce alloys or semi-finished products in different shapes and sizes in the shortest time.

4. Repeatability of production using programme saved in and also remembered from menu system.

5. Controls system Siemens which can guarantee the quality of our Jewelry Casting Machine

6. Vacuum chamber design, the whole process will be under the complete inert gas protection of crucible and die system.


Step 2: Rolling mill treatment of gold bar surfaces to obtain the required thickness and brightness


In this step, the silver/gold bars will be pressed repeatedly through rolling mill. The high hardness roll material of the tablet press can press 24K gold into a flat and even density full gold strip. Each rolling can make the gold bar wider and thinner, with higher density until achieving the thickness required for the coin, laying a foundation for subsequent processing. We can anneal the metal to increase the ductility and make the pressing more smooth.

The intelligent system can adjust the thickness of the sheet metal through parameter setting, and extrude through the hard and incomparable roller shaft. Install the reeling tension control device, and reeling wheels on the left and right sides can automatically balance the reeling, which can be retracted and released freely with excellent extension effect.


Problems in the operation of tablet press:

Do not adjust the pressure joint too tightly once, otherwise it may cause damage to the machine. In particular, it should be noted that the counter roll of the electric tablet press rotates rapidly. When inserting the metal parts into the tablet press with your hands, let it go as quickly as possible to avoid crushing the handle of the counter roll.


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Step 3: Obtaining the coin blank

This process is to form the shape of the coin by hydraulic punch machine. The coins sold in the market are usually round. But if you want other shape, CDOCAST hydraulic punch machine can also achieve. This step is very important, because the coins may be regarded as fake or defective goods if their shape is not perfect and cannot be sold in the market.


CDOCAST hydraulic punch machine is mainly composed of four column body, oil cylinder, hydraulic system, limit device and electric control system.

1. The machine body is of four column structure, which is simple and compact and convenient for observation on four sides.

2. The main cylinder is a piston type oil cylinder, and the working principle is that the fast cylinder oil inlet can realize the fast downward movement of the moving crossbeam.

3. The hydraulic system adopts slide valve control to achieve the circulation action required by the process.

4. The electrical system adopts relay control to realize the process action cycle of the machine according to the requirements of the hydraulic system.

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silver coin

Last but not least, in order to ensure the minimum burr and edge of the blank and avoid any pollution and scratch, annealing and polishing are carried out immediately. But be careful not to polish too much, which may make the coin lose its mirror effect.


Step 4: Embossing

The meaning of embossing is to press the die of a coin on the press to punch the obverse and reverse patterns of the coin on the blank. After this step, the unique coins come out and can be sold to the market.

CDOCAST hydraulic logo marking machine is equipped with the following electrical protection device, so the operation will be safe:

1. Short circuit protection of main circuit and control circuit is realized by fuse.

2. Overload protection of motor is realized by thermal relay.

3. This machine is equipped with “emergency stop” button SB1 to realize emergency stop.

4. The machine has been installed with photoelectric protection device to ensure the safety of the operator.

5. The machine is equipped with a special grounding device for the electrical box.

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Additionally, mold design is a unique and important link in the coinage process. After strict examination and approval of the subject matter, patterns, through the sophisticated and exquisite carving of the mint, combined with the use of modern precision equipment, the design intent is expressed in the mold. In order to highlight the visual effect, the main relief of the depression has a fine frost surface, and the higher places need to be ground into a mirror surface.

In order to maintain the original color of the coins within a certain period of time, the surface of each coin must be protected. At the same time, it should be placed in a plastic box, sealed with a plastic film, and then put into a specially designed packaging box, and all the finished products should be subject to strict inspection.

*Chapter IV – Guide purchase of minting machine

If you want to mint high-quality coins, purchasing good coin casting machines is very significant. The following machines are essential for you to make good coins:


1. Jewelry Continuous Casting Machine/ Vacuum Bullion Casting Machine

2. Rolling Mill

3. Annealing Furnace

4. Hydraulic Punch Machine

5. Hydraulic Press Machine


When selecting the equipment or machine for gold coin minting process, it is necessary to identify whether the equipment has the following functions:


1. Does the machine provide gas (vacuum) protection?

A good gold coin has a glossy surface. In the manufacturing process, it needs to provide a vacuum environment to prevent oxidation and shrinkage. Otherwise there will be rust layer on the surface, affecting sales and causing great loss. Therefore, gas protection is very essential. The jewelry continuous casting machine / vacuum bull casting machine sold by CDOCAST are all vacuum protected, and the gold bars produced have mirror effect.


2. Is the coin minting line automatic?

With the development of technology, high efficiency and intelligent operation are pursued by every manufacturers. Additionally, it can help reduce the labor. 1-2 workers is enough for the whole coin minting line. Press the button to start the machine and it will be produce the goods as you want. If you want full automatic line, CDOCAST can also offer you with the manipulator. More details, please contact us.


3. Is your gold coin making machine compatible with other equipment?

Most of the coin making machines are used alone. They need to be collaborated with other devices to complete the work. Therefore, it is important that the equipment you purchase can work smoothly with other types of equipment.


4. Is coin minting line environmentally friendly?

The issue of  environment protection is always a focus in our current world, and will be a long-term problem existing in future. In some countries, the requirements for environmental protection are strictly and clearly stipulated. So you have to focus on whether the machine will produce waste gas and waste water, which will pollute the air, soil, water and so on.


5. Will the equipment supplier provide instructions or video guide?

You may be in contact with the production line for the first time, and you are not familiar with the operation and production process of the new line. A manual or the guidance of an experienced person will help you quickly get familiar with the whole process and operation soon , improving efficiency and avoiding mistakes. Additionally, the instructions needs to mention the maintenance methods and troubleshooting to help you maintain your own machine better.


6. Whether the manufacturer can provide satisfactory after-sales service?

Normally, the manufacturer will provide a one-year warranty period. In case of non-human damage, if there is mechanical failure, you can return the machine for repair or replace the parts for free. For brand new machines, there may be few problems. But some gold coin manufacturers will buy second-hand machines considering the cost, there’s gonna be a lot of glitches. So don’t consider the manufacturer that the warranty is less than one year or even not provided, CDOCAST will offer 2-year warranty.