The role of vacuum in synthetic diamonds' production
Mention diamonds and most people will associate that with the jewelry sector. They will also have in mind that such gems are to be found in
mines and sometimes won under severe conditions (“blood diamonds”). For such reasons, the industry already investigated in the 1950s how to
produce synthetic diamonds.
Today,
there are several processes available to create artificial diamonds. Not only for jewelry where even experts are challenged to
differentiate a natural diamond from an artificial, but also for the much larger market for diamonds in the industrial sector.
Four outstanding properties of synthetic diamonds
The key properties of synthetic diamonds that make them so interesting for the industrial sector are:
Mechanical (superior hardness a chemical inertness)
Optical (high transparency)
Electrical (semiconductor properties)
Thermal (highest heat conductivity)
Some typical industrial application examples are machining and cutting tools, window material for transmitting infrared and microwave
radiation, and heat sinks for lasers and transistors. Synthetic diamonds are also the base material for semiconductor wafers and Qubits for
quantum computing.
How are diamonds obtained?
Traditionally diamonds were naturally formed billions of years ago in the earth’s crust by carbon atoms being exposed to intense heat and
pressure. However, due to technical advances, a new source of synthetically grown diamonds was created. This market can be divided into 2
main manufacturing methods:
HPHT (High-Pressure High Temperature)– This method is based on how diamonds were naturally formed - compress carbon and add heat. The
equipment footprint often has large and limited process control.
CVD (Chemical Vapor Deposition)– This method is based on creating a vacuum environment and then introducing specific gasses to trigger a
reaction. The equipment footprint often has a small and excellent process control.
MPCVD (Microwave Plasma CVD) growing process
Due to its small footprint and excellent process controls, the MPCVD growing process has gained in popularity. One important part of the
MPCVD process is the creation of and maintaining optimal vacuum conditions inside a growth chamber. A typical growth chamber setup looks as
below:
Close chamber and evacuate chamber for conditioning, heat up substrate
Introduce hydrogen
Turn on microwaves and generate plasma (~4000 °C) above the substrate
Introduce process gases and start epitaxial growth
Methane – carbon source
Ethanol, Acetone, or Oxygen (optional) – helps improve the quality through oxygen plasma etching effect
Nitrogen (optional) – helps speed up the process (learned from experience and made MPCVD growing feasible economically)
1 to 4 weeks of growth period
Which are the vacuum pump requirements for the growth period?
Initial pump down to about 2E-2 mbar base pressure
Maintain pressure (100-300 mbar, typically in a range of 100-130 mbar) while process gasses flow
Low-pressure cleanup of diamond color after production
Nowadays, oil-sealed rotary vane pumps are typically used in the MPCVD process. This is because these pumps are very well suited to
achieve low conditioning pressure but also because they are mainly designed for continuous operation at fine vacuum. Additionally, these
pumps face poor lubrication, overheating, or high oil loss when operating for days in the rough pressure phase required by this process.
Advantages of oil sealed pumps
The oil lubrication of these vacuum pumps is secured by a built-in oil pump, which also enables a uniform oil distribution at
rough pressure operation, whereas standard pumps without such oil pumps could fail.
Our range of rotary vane pumps is designed for operation at rough pressure and provides a perfect solution for the diverse pressure
requirements of this growing process:
The low ultimate pressure can easily meet the initial pump-down request, but the design of the pump also allows continuous operation at any
(even rough) operation pressure
Integrated high-efficiency exhaust filter that can reduce oil losses to the technical minimum. The oil stays inside the pump!
Compact design. There is no need for an external exhaust oil mist separator with oil return
The Ash Air range of rotary claw vacuum pumps is the best alternative to rotary vane pumps. A vacuum claw pump is virtually zero maintenance and compared to rotary vane pumps can work at vacuum levels of 400 to 1000 mbar without overheating. Rotary claw vacuum pumps are the best choice for CNC guided wood routers.
The Ash Air range of humble liquid ring pumps is still the most reliable form of large volume vacuum generation available today. These liquid ring pumps are simple to use and very reliable, and the best option when sucked air contains a large amount of saturated gas.
Dry and oil-sealed vane vacuum pumps are robust, affordable and easy in maintenance. You can use DVP vane pumps for wide range of application, for skin packaging, holding, lifting, thermoforming.
We have a great range of new and hire blowers from single stage ring blower through to large lobe blowers, and we also stock the service parts for common blowers across many brands.
Our roots blowers, side channel blowers are built to last, and are backed up by our promise of excellent customer service to keep your business performing well day in and day out.
With hundreds of years of combined experience and a broad product range, Ash Air is a great partner for your vacuum pump operations.
From rotary vane pumps to screw pumps and accessories, we have a large variety of products. We also have a dedicated
applications team ready to calculate the ideal pump configuration. With a global support organization, we can support your manufacturing
operations wherever they may be located in New Zealand.
Do you have an idea for our #expertcorner? Let
us know!
Who we are and how Ash Air can help your business!
Ash Air has been around in New Zealand since 1979, and we’ve grown into a nationwide company with international support and a
reputation for quality and reliability.We look after all things compressed air for your business!
Reciprocating, Screw, air compressors
Vacuum pumps
Nitrogen
An extensive line of air treatment components
Ash Air's range of Chicago Pneumatic, Alup, Pneumatech, and Quincy compressors are used extensively around the world in industries
ranging from oil and gas to food, automotive and farming, and we bring you these world class compressors here in the land of the long white
cloud.Our technicians are compressed air equipment experts and are dedicated to addressing customer needs. Supported by a 13 locations
nationwide, Ash Air offers one of the widest selections of compressed air equipment and parts available today in New Zealand.
Reliability and Efficiency
With Ash Air compressors, you can count on reliability and high performance for even the most demanding applications. We focus our
efforts on the following:
Air compressors come in many types, rotary screw, piston, scroll, reciprocating, some are oil-free and other air compressors require oil
lubrication. Like many businesses, an efficient air compressor is at the heart of their operations. So, which type of compressor should you
choose? What makes a compressor, like a rotary screw, unique? Here are some clear cut benefits of equipping your business with a rotary
screw compressor. Â
Read More…
In the world of compressors, there are often significant and unutilized energy-saving possibilities including energy recovery, pressure
reduction, leakage reduction and optimization of operations through correct choice of a control and regulation system as well as the choice
of compressor size.We are going to take a look at some of the opportunities for minimizing the compressor’s operating costs.Â
Read More…
Many installations that produce compressed air offer significant and frequently unutilized energy
saving possibilities in
the form of waste energy recovery. In large industries, energy costs can amount to 80% of the total cost of compressed
air production.
However, a lot of this energy can be recovered, which in turn will save you a lot of money.Â
Read More…
Liquid water in compressed-air systems can lead to rusted equipment and unresponsive controls. Anyone who uses compressed air will, at some
point, find liquid water in the air distribution system. This can be anything from a nuisance to a serious problem, depending on the
application. If water might corrode equipment or introduce bacteria, removing it is critical.Â
Read More…
Liquid water in compressed-air systems can lead to rusted equipment and unresponsive controls. Anyone who uses compressed air will, at some
point, find liquid water in the air distribution system. This can be anything from a nuisance to a serious problem, depending on the
application. If water might corrode equipment or introduce bacteria, removing it is critical.Â
Read More…
Whenever most people think about a compressor, they probably have a piston compressor in mind. You might already know there are two basic
principles of air compression. One of those is the principle of displacement compression. There are a lot of compressor types that classify
as a displacement compressor. The piston compressor is one of them, oil-lubricated or oil-free.Â
Read More…
Once you have the size and type of
compressor figured out, one last question remains, should I go with an oil lubricated or oil-free air compressor. To not overcomplicate the
answer, your choice should be based on the application and process that the compressed air will be utilized in.
Read More…
Like all compressor types, rotary screw models do require periodic maintenance. Thanks to the simplicity of the internal components,
maintenance is relatively easy on most rotary air compressors. As long as you stick to a rotary screw compressor maintenance schedule, you
will likely be rewarded with many, many years of optimal productivity from your machine.Â
Read More…
Did you know, the biggest part of the air we breathe is nitrogen? Everyone needs oxygen to survive, however air is made up of 78% nitrogen,
only 21% oxygen and tiny amounts of other gases. Although, the human body does not use this nitrogen, it is very helpful in various
industrial applications. There is an unlimited source of nitrogen readily available, allowing you to achieve needed purity at a fraction of
your current annual nitrogen cost.Â
Read More…
If you notice that your compressor is getting hot and bothered, there may be heating issues affecting your air compressors performance. Did
you know that an overheating compressor is top of the pops for being the most common cause of compressor failure.Â
Read More…
A rotary-screw compressor is an air compressor that uses a rotary-type positive-displacement mechanism, typically used replace piston
compressors where large volumes of high-pressure air are needed, either for large industrial applications or to operate high-power air
tools.Â
Read More…
Have a look around and what do you see? What are you thinking about? Your next holiday to Queenstown maybe? You might go snowboarding with
the kids or have some alone time at the Day Spa. Whatever holiday you choose, compressed air is involved in some way, without you even
realising it! Â
Read More…
There are crucial reasons why you should service and maintain your compressor regularly, with the most common issues being piston failure
caused by wear of components, increased friction, corrosion, reduced cooling, overheating bearings and components, clogging of air filters.Â
Read More…
Our passion for energy efficiency and cost saving derives from the concern for our children’s future. Analysing the efficiency of your
system is a brilliant way to start saving.
Read More…
Compressed air is all around us, from the air in a balloon to pumping up tires on your bicycle. In this article we will explain what
compressed air is and how it is created. Whether you know it or not, compressed air is involved in every aspect of our lives, from the
balloons at your birthday party to the air in the tires of our cars and bicycles. It was probably even used when making the phone, tablet or
computer you’re viewing this on.Â
Read More…
One of the biggest challenges is to correctly size your new air compressor. Similarly to everything else, new compressors available on the
market are more efficient and employ better technology, therefore you have to understand the application and usage to size the machine
correctly. Choosing the wrong air compressor for your facility can lead to problems with production and or increased costs due to wasted
energy.Â
Read More…
Once you have the size of the air compressor figured out, the
next thing to do is to decide on the type of compresor you will need for your application - piston, rotary screw compressor etc. Let us take
a look at two of the most popular options available. When choosing the right type of compressor, you should ask yourself the following
questions:
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​Which vacuum pump do I need? - this is one of the most frequent questions we receive and this is understandable, because there are number
of technologies which can provide the same vacuum level and pumping speed. Here is quick advice on how to choose the best vacuum pump for
your needs.Â
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You may be asking, why does my air compressor start, then stop? Allow us to take the guessing out of it. We understand your pain. We know
that a compressor problem can quickly result in hours (if not days) of production downtime and loss of revenue. When your compressor
continuously shuts off from on, we refer that as a short cycle. There are a few reasons that a short cycle may be happening with your
compressor.Â
Read More…
Air compressor leaks are very common in all applications, but can be very costly and difficult to find. On average, 20-30% of the compressed
air used in a manufacturing plant is wasted as leaked air. Finding and fixing these leaks can save your business thousands of wasted dollars
a year.Â
Read More…
When installing a compressed air system into a business, people often look to PVC piping as an option to build a piping system because it is
cheap, versatile and easy to install. However, using PVC pipe in any compressed air application is extremely dangerous and NOT recommended
by multiple associations and manufacturers.Â
Read More…
Changing the oil and oil filters on your compressor is one of the most common routine maintenance tasks to perform to keep your compressor
running efficiently. After you remove your old oil and oil filter, you may find yourself wondering, “Where do I dispose of these?”, or “Can I
just throw them in the trash?”. Because oil is toxic and a pollutant, disposing of your old oil and filters is not as simple as just tossing
them in the trash.Â
Read More…
Today,
there are several processes available to create artificial diamonds. Not only for jewelry where even experts are challenged to
differentiate a natural diamond from an artificial, but also for the much larger market for diamonds in the industrial sector.
