Why is the design of fixtures so important?
The design of the fixtures defines three decisive properties regarding quality and economy of the coated product. At first the fixture defines the position and the movement of the product relative to the evaporator sources. With this the film thickness and the distribution of film thickness on the different functional areas is controlled.
At second the distance between the functional areas and with this the free space around the product defines the number of available ions and electrons, which will hit the surface. This influences the ion cleaning of the substrate but also the density and hardness of the applied film.
Last but not least the design of fixtures defines the number of products, which will fit in one batch, and how long the cycle time will be. For the same style of coating furnace the design of fixtures may have higher impact than an expensive process development.
How do I achieve a good and cheap solution?
4pvd offers design, project management and manufacturing of high quality fixture systems without risk. Against a sketch of your product or a ISO definition code we will provide a noncommittal proposal including different options from design only until complete supply of the fixtures.
From this proposal you will roughly get, how the fixtures will look like and how many pieces will fit in your chamber. As a minimum option 4pvd offers to prepare this draft for your design department, so your experts can transform it into manufacturing documentation.
As a further option 4pvd offers to provide complete manufacturing and assembly documentation for your workshop or your suppliers. As a third option 4pvd offers to supply the complete fixture system to you. If the request comes in time the fixture can be in your coating production prior to your products.
Can I manufacture my fixtures in my own factory?
If the right documentation for the manufacturing process and the assembly is available, usually all qualified work shops are able to build and assemble fixtures for PVD process. Prior to and during the assembly roughly the same requirements as for PVD coating are necessary.
For workshops, which do not have experience with the manufacturing of PVD Fixtures we recommend a training course and audit regarding the basics and necessities of the relevant process. 4pvd will be happy to assist you to undertake the relevant steps.
Additionally 4pvd offers training related to draft and design of PVD fixtures. This is to recommend, if your design department intends or needs to care about fixtures on a regular basis.
Beside of this 4pvd offers a lot of tools to make your life easier. Just have a look at our batch calculator, which enables you to submit proposals, without an intensive calculation process. The batch calculator is also available on EXCEL basis and can be adapted according to your demands.
Why does 4pvd provide so many different styles of fixtures?
The necessity for the fixture systems Nova, Colt and Sphere can easily be explained by use of examples like drills, mills, punches and taps.
Taps usually require a thin but very constant film thickness along all the cutting edges. For this the axle of the taps is positioned parallel to the surface of the evaporators, and than rotated around the tool axle. This request is fulfilled by the colt fixtures
Even though drills and mills can also be coated by use of the colt design, this way will not achieve the optimum film thickness distribution along the functional areas. If drills DIN 338 are coated in sphere fixtures with a tilt angle of 28°, a ratio of coating thickness of 1:1 on the tip versus the diameter can be achieved. As a nice side effect, the number of pieces is higher for sphere fixtures, as the batch calculator proves.
For micro drills, mills and punches with a short working area sometimes the coating thickness is only specified for a very small area around the tool tips. Now the fixtures nova can be used. If the demand on the coating quality is not extremely high, nova will place a huge number of tools into your chamber.
Rotating tools with cutting edges on both ends are ideally coated in boxer fixtures. Boxer fixtures are unbeatable in terms of quality, safety and economics.
We will be happy to assist you with the selection process of your individual and optimized solution.
What kind of materials should be used for fixtures?
At the maximum process temperature the base materials for fixtures should provide:
- sufficient strength
- low evaporation pressure
- resistance against corrosion
- electrical conductivity
Common material for general applications is stainless steel and for tiny parts like springs and rods Inconel or Tungsten. For bearings bronze materials are useful or other materials with coatings. Magnetic materials are available up to 500°C.
Is the same style of fixtures suitable for different kind of coating plants?
In general the 4pvd fixtures can be adapted to multiple kind of coating systems. By this the flexibility of your production is significantly increased. By the way: In general the life cycle of fixtures is usually longer then the one of PVD coating systems.
In any case a new qualification process will be necessary, as the differences between the process may cause that the position and distance of the products have different impact on the coatings properties.
For which applications are the sphere fixtures designed?
Sphere fixtures provide best profit in case of drill and mill coating. However it is necessary, to have enough pieces available, to fill complete towers with tools of one dimension.
In opposite to the colt fixtures, the design of sphere fixtures is influenced by the diameter and the length of the tool. Therefore colt is tie better solution to combine different length and different diameters in one table.
Conclusion: Sphere is for tool manufacturers with high volume and for large scale coating service production. Colt is rather for small scale production or for tool repair.
Do you recommend to use temporary fixtures for sample coating?
This is a difficult question. We know, that sample coating always suffers from a leak of time and budget. It is risky to invest in new fixtures without a contract about the coming business.
On the other end a not optimized fixture may result in a lower quality which may bring your coating only into second place. Beside of this it has to be understood, that the sample coating is from customers point of view a kind of qualification run, and any subsequent change of the set up will require a new qualification.
Therefore 4pvd strongly recommends, to use fixtures as similar as possible to the production design. Especially the position of the products relative to the evaporators and the distance between them should be the same.
Do optimized fixtures provide a competitive advantage to me?
The advantage which can be achieved by the use of optimized fixtures is huge. There are only few manufacturers of PVD coatings, which can truly state, that they possess a unique coating technology. But among comparable coating units, the fixtures can make that decisive difference in terms of economics and quality, which outperforms the competitors.
To get this, it is important, to check out the real requirements from the customer very quickly and transform it into a reliable optimized fixture system. 4pvd will be happy to assist you exactly with this task.
Coating service or in house production. How do I choose?
The first benchmark is always the volume. Whenever the total expenses for coating service for the next two to five years will be higher than a turn key production line for the same products, one should consider to install this production line.
Reasons which may shift this decision to earlier dates are difficult logistics e. g. long delivery terms or expensive packing, or the desire to have a unique position or unique products. A good network of coating service facilities in the neighborhood may also shift this decision to the future.
Often the parties believe, that the change from coating service to in house production is a big break. For the long term economical and technical development of the customers products it is much more of advantage, if the customer, the coating service company and the furnace manufacturer continue to work together.
Which PVD process is the right one for my applications?
Among the most used technologies for deposition of functional coatings for tools or precision parts are those with crucible, the arc evaporation and the sputtering.
Crucible technology is fading, as the coatings of today mostly contain more than metal compound and are difficult to evaporate from molten sources. Also, as the the vapor always comes from the bottom where the crucible is, there is always a gradient in thickness distribution.
Sputtering process are more and more used, as they are able to deposit all the modern complex coating materials and partially even those nonconductive materials. Beside of this sputter coatings are most clean and homogenous.
Arc evaporation can handle most of the today’s coatings with good quality and excellent economics. But arc evaporation is more limited in terms of coating material choice than sputtering. To suppress the typical macro particles (or droplets) many special designs of the evaporators are introduced, but most of them pay the advantage of droplet reduction by loss of efficiency.
Where and how do I find the right PVD furnace?
A majority of PVD coating systems is manufactured in central Europe. All of these suppliers offer and advertise their products as the one and only solution. You as a customer will usually find out after more than one year, whether the purchased equipment fulfills these promises.
Extremely helpful for the evaluation of a supplier for PVD coating technology is the chance to use the suppliers facilities for coating service over a period of some month. If coated products from this period can be used as reference, the probability for surprises for both parties is significantly reduced.
If coating samples are evaluated, it is very important, that these samples are produced on the same kind of equipment, which is part of the proposal and if the samples are produced under production conditions. More details about the influence of different fixtures and the distance of the substrates during the coating process you will find in the part FAQ Fixtures.
Technical acceptance criteria, which specify properties of the coatings, the batch size and cycle times and benchmarks related to the availability and the cost per piece grant a minimum of bottom line. Coating furnace manufacturers do not like to guarantee any performance of the customers product in the field, because they can hardly evaluate or influence them.
What’s important if I want to buy PVD technology?
Whatever you are going to buy, you will spend a lot of money for it and you will probably have to work for a long time with it. If this is your first PVD installation, you will probably not yet have enough experience, to make this decision properly. We will try to list the minimum requirements for your next PVD installation as follows:
Your next PVD system should:
- provide acceptable quality, reproducible and reliable.
- have an acceptable ratio of coat and time per piece.
- be flexible to be able to deal with different batch sizes.
- be upgradable for future tasks.
Large suppliers or those with high market share promise professional support, experience and reliability. Small or local suppliers may balance this by high flexibility and strong support. Suppliers of PVD coating systems, which run their own job coating service for similar products, know the market and the products. But this advantage my be swallowed by the risk of a possible competition against the manufacturer of the coating systems.
Even though the advantages from an exclusivity for a market segment seem to be huge, there are usually much bigger disadvantages hidden in an exclusive supplier situation.
What are the main differences between the common PVD processes?
The main difference between the common arc and sputter evaporation processes is the generation of the vapor, which happens in one spot for the arc evaporation and happens simultaneously on the target surface for the sputter process. This leads to several advantages but also limitations for the variations of both processes which the following table roughly displays:
choice of coatings
efficiency e. g. TiN
efficiency e. g. TiAlON
efficiency e. g. Al2O3
How can I hire and qualify my personnel?
To operate a PVD production efficiently but also to maintain a good relationship to a coating service supplier, it needs qualified and engaged personnel at the customer. The PVD technology or relevant elements of thin film coating technology are not the focus of any classic education. But still it is possible to equip engaged employees with the necessary know how, to run the coating production with profit.
According to our experience the profound knowledge of of the coated product and emphasis is of much higher importance than knowledge of PVD technology. Only if you intend to undertake your own research of coating basics and applications, you should look for people with academic knowledge of PVD technology.
Beside of the initial training and level of education, it is of very high importance, that this level is maintained and improved during the years of operation in order to improve quality and economics continuously. Other than the initial training, which is greatly provided by the supplier of the equipment in order to meet the acceptance criteria, training at any later time may be difficult to obtain or very expensive. Contracts for maintenance and retraining may improve safety and quality of the products.
Analysis of the production on a regular basis and retraining of the employees can help to keep the production at the state of the art. External experts may be very useful to identify failures or give hints for better methods.
What kind of quality control methods do I need?
If the coating thickness, the adhesion and the optical appearance of the coating meet the specification, in most cases the main requirement for the coated product are fulfilled. The next level of investigation may look for the micro hardness and micro structure of the coating.
It is important for all methods and apparatus for quality control, that they are immediately available and that the personal in charge is able to quickly perform the necessary tests. Many times the used methods do not provide standardized numeric results which limits SPC and CIP methods.
In order to avoid damage to the products by processing the quality control and in order to provide a reproducible geometry and topography as reference we recommend to use little pieces of reference in each batch. These reference pieces allow to characterize the PVD process quite well, but do not guarantee anything for the original products.
As the interactions between substrate, coating and application are extremely complex, finally only the performance test provides reliable results. If the original test conditions would take to much time, eventually increased test conditions can help to provide a satisfactory result in acceptable time.
How do I chose between standard and custom made coating equipment?
This question can only be answered after detailed analysis of the product, the market and the prognosis. As usual first the quality and than the economics should be looked at.
Custom made equipment can be optimized according to the product and especially for products with extraordinary geometry they are sometimes the only solution. In case of custom made equipment even the manufacturer can not provide the same level of experience as for a standard furnace, and this is not only of importance for the set up of the machine but for the years coming later.
In case a standard furnace is used, the manufacturer and the customer basically can adapt the fixtures and the process to solve the current application. It might be a critical disadvantage, that the design of the standard furnace may force the application and the process in to a parameter window, which may cause the project to fail.
An interesting alternative might be standard furnaces built on a modular base. In this case the vacuum system, the plasma electronics, the control system and the user interface can be taken from the serial equipment of the original manufacturer. The evaporators (standard or custom made) can be placed into an adapted vacuum chamber in that way around the substrates that the configuration of a custom made equipment is achieved.
What kind of tools can I use for material flow and logistics?
The importance of well organized material flow and tools for logistics is mostly underestimated. But if the part of the sales price of a product which is related to the coating is in the magnitude of 1,00 EUR, the part of the manufacturing cost which is outside of the PVD furnace can easily be higher than 50 % of the total cost.
Many suppliers offer proved systems for storage, transportation, identification, documentation and so on. Building the interfaces from the coating systems and quality control to existing ERP or IT systems can improve the process, but can also create huge cost and friction.
Even the process of production planning, e. g. with the aim to reach maximum utilization of each batch can be supported by commercial software, but the process has to be defined in that way, that the planning tool supports the production and does not slow it down.
Matrix codes appplied by Laser Ident Systems can improve the material flow especially in jop coating production. This codes can be applied even on smallest products and easily be read with hand held scanners.
What is not a 4pvd product or service?
a4pvd does not offer coating service. But we like to assist you to find, evaluate and qualify one of more than 60 coating service centers in middle Europe
4pvd does not build PVD coating furnaces. But we like to assist you to specify your needs and through the whole process of purchasing, installation and production. We do also offer training and production coaching for customers and suppliers. And of course we offer our fixture systems.
How do I pay for 4pvd service?
Our service is charged according to methods depending on the kind of the service:
In common projects the service to reach milestones are defined prior to the project launch and are charged after the milestone is reached.
Short term services may be charged upon hourly or daily base after the service is provided.
For services which are usually used on a random base, there may be flat rates e. g. on a monthly base.
There will be no charges, which have not been defined and agreed previously in terms of date and sum.