Do you know what is the force, rebound force and click ratio means in metal dome product? Those are some basic performance we should know if you are going to buy metal dome, hereby we will tell you.
CP means compression peak force, we usually use it to define the operation force of metal dome, Its means the biggest force you pressed on the snap dome and make dome from a short opening status to the conductive status. CL means the compression low force, we also call it as rebound force. Its means the biggest force when the dome back from conductive status to opening status. Generally people use G(gram )or N (Newton force) to define all kinds force concepts. Please also refer to our blog how to test the life of metal dome .
And click ratio, someone also name it click feeling (CC) has a equation to define: CC(%)=(CP-CL)/CP*100%, this CC result(click ratio) is commonly required at 35%~6o%, if the click ratio is too high then it will affect the life cycle of metal dome. Briefly, you can also refer to the below chart to understand these concepts.
Fore test report for example Best Technology, your best partner in Asia, is professional for dome sheet and dome switch more than 15 years in China. Please feel free to contact us if you have any question about snap dome.
The key point to determine the quality of metal dome and snap dome is that whether the metal dome is cleaned or not. If the metal dome switch is not cleaned, it will affect the conduction of circuit board, which causes a functional problem, so the process of cleaning is very important. The cleaning of metal dome is done by Ultrasonic, Steps as below: 1)Put unclean snap domes in box
2)Using a special chemical potion with about an hour of cleaning for tactile dome
If cleaning is not thorough, there may be laminated, rust and stains will be produced. So we need to check the appearance of metal domes carefully, such no scratch or crush on the surface and no deformation, spots, dirty.
Best Technology, your best partner in Asia, is professional for dome sheet and dome switch more than 15 years in China. Please feel free to contact us if you have any question about snap dome.
As we already know there are two methods to manufacture metal dome array: laser-cutting or tooling produce . Usually when the dome sheet exceed than 150mm we will suggest to open a tooling to produce it. Is this the only way to make a snap dome array which dimension exceed 150mm? The answer is not.
Actually, for such super large size metal dome array (usually this super-sized dome array is more used on the keyboards), we have another method to do it beside tooling produce, especially when your demand quantity is not very large, consider from the perspective of cost saving we will suggest to make such dome sheet(also name dome cover) by laser-cutting. The precondition is we need dividing this super large dome array into several parts according the layout of metaldome, then we can produce those dome sheets by laser-cutting as supposed.
Take an example for above PCB boards, the dimension is 212*161mm, except tooling produce we take another method as laser-cutting, we divided it into 3 parts accoridng the distribution of the snap domes( see the white frame line area in the PCB board), then those 3 dome arrays won’t exceed the range of laser machine, thus its very easy to produce the metal dome panel and save much cost as well.
Although the assembly efficiency maybe a little bit slower than the whole sheet dome array assembly, but its does not matter, because we marked a white frame line on the circuit board, and we can also use it for alignment when assemble metal dome array on the PCB board, its very quick as well. For the assembly of dome array please visit our blog “How to Assemble Adhesive Tape of Metal Dome? “.
Best Technology, as the top 5 metal dome & dome array manufacturer in China, we have more than 15 years experience in snap dome, metal dome sheet and tactile membrane switch industrial, our metal dome is equivalent with Snaptron & Nicomatic metal dome,we can always provide you the best solution for your dome switch project. If you have any doubt or inquiry about the snap dome please kindly call us or email us at any time.
We usually make metal dome array or dome sheet with the standard and normal tape (datasheet of PET adhesive ) . But sometimes we still would hear feedback from some customers that dome array can not be sticked firmly and strongly on PCB (print circuit board) or FPC (Flex PCB), see below photo.
Specific reasons are analyzed as follows, wish it would be helpful for your product design..
The dome film sheet made with high dome force and stroke (height) as the customer required, lead to the adhesive can’t be pasted well on board, because adhesive layer will be jacked up.
The adhesive tape area of snap dome array reserved and pasted in the customer’s drawings and specifications is not enough or too little. Generally keep a distance of at least 2.0mm above.
3. The viscosity tolerance of each batch of materials is different. If the material tolerance goes to the lower limit and the above two factors are added, the adhesion may not be very firm.
In general, our metal dome array is unlikely to have such a problem. For these special specifications, we can generally use a more viscous adheisve tape (such as 3M) to solve this problem. We have stronger adhesive materials for some special specifications of the snap dome sheet. However, there is a disadvantage is that it is not easy to tear after sticking, so you should stick to a good position at one time.
Best Technology, your best partner in Asia, is professional for dome sheet and dome switch in China. Please feel free to contact us if you have any question about snap dome.
Many people think that the production of metal dome array is very complicated, in fact it’s not. It’s easy to produce and the cost is not very high. Let me take you through the production process of metal dome array.
As all know, we need to control the production environment of our products well, so before we enter the workshop, we must put on dustproof overcoat, cap and shoe covers, and then be dusted by dust removal system in a closed room.
Firstly, we need to do incoming inspection, raw material of PET adheisve with width, thickness, appearance and tension and metal domes switch with life times , force, diameter, height, burr, resistance and appearance, in order to make sure the snaptron domes are all same standard and meet customers’ requirements.
There’re many kinds of PET paper with different colors, such as white, transparent, black, gold, etc. The gold one is most expensive and few customer use it. We often use transparent and white adhesive.
There are two methods to make snap dome array, one method is by laser-cutting, that produce with small qty, a litter longer lead time and higher unit cost, but could save tooling cost; And another method is by machine with tooling, that we can produce big quantities and save manufacturing cost in this way, but the customer need to pay tooling fee.
Now please let me briefly describe the process of how to make dome array by laser cutting. Laser cutting, the temperature of its operation can be 500 degrees. The cost for this manufacture is lower, but the processing charges is a little bit higher.
Firstly, we need to laser cut spacer hole (dome hole)
Second, do first article inspection. Put dome array on assembly Jig, check whether the snap dome hole on assembly Jig and spacer hole on spacer overlap.
Third, we can place other materials on the top of spacer to meet customers’ requirement after spacer production is finished, such place mylar, silver paste, rubber glue or LGF layer. No fingerprints are allowed to be on the spacer, so we’ll gently scrub the spacer by alcohol, and we can have pony-size spacer after machine cutting.
After that, we need to laser cut outline and air channel.
And then, Dimensional measurement for this dome array.
There are dots on fixture, when the fixture is operating, we will put the snaptron domes on it, and the dots will fix the metal domes on them. Put the spacer (sticky side) on the top of Snap domes in dots until all the metal domes switch adhere to it. This is what metal dome array first looks like.
Afeter assemble sanptron dome on array, we need to check whether have double metal domes. Normally we use magnet to check it, will put metal dome array on powerful magnet, if there’s needless Snap dome, it can be attracted away by magnet.
After check the doubel metal dome, we’ll settle release paper on metal dome array. Finally we need to do finished product inspection and Pack & Shipping.
Do you know how to make dome array by laser now after reading this article? Please feel free to contact us if you have any question. And I will introduce how to make dome array by machine in next article, please pay attention for us always.
Best Technology is your best partner in Asia, we are always here and waiting for your coming warmly.
The Second factor: Life test method. Maybe you’ve been in this situation, you ask same metal dome from different supplier, but with different life cycles and you are confused about it. The reason is that when we use different life test method, such the diameter of test probe, material of test probe, test speed, test force to test the metal dome, the result will be different.
For example, under the same test speed and force, tungsten steel test probe has a different test result compared with silicon test probe. It’s easy to guess who has the tougher test conditions.
So the same principle, 1.5 times test force has different test result compared with 1.1 times test force.
The Third factor: The click ratio.When click ratio is too high, the rebound force will more lower, thus the metal dome is easy been sunk after long time pressing, so it is easy to reduce the life of metal dome.
The Fourth factor: Accuracy of assembly. The life is the best when we always press the center of metal dome, but the large deviation of assembly, it will cause us to miss the center of metal dome and reduce the life of metal dome, and also will have other issues.
And the life time are also related with the shape, height of metal dome, tooling produced, and operation habits. Usually round type will have better life than four legs and triangle, higher height with shorter life of metal dome; The more precise the mold, the better the life; If the operator press the dome with excessive force for long time, its will reduce the life of metal dome as well.
After reading this article, you must know more about metal dome now. If you still have any doubts about life cycle of metal dome, welcome email us firstname.lastname@example.org or call us +86-755-2909 1601, we are happy to discuss more with you.
Why do some customers have this requirement? That is because they need to assemble metal dome array(dome sheet) before welding, it would need bear over a high-temperature(over 200 degrees). However, the maximum temperature of the metal dome array material can bear is 125 degrees. So the material will be melt after high-temperature oven, this is certainly unacceptable.
If this requirement must be obeyed, we can change to use one material which can bear high-temperature. However, the difficulty and cost of this kind of material will get much higher than normal one. Therefore, it is recommended that we can assemble dome array(dome sheet) after welding, this is a very reasonable and convenient way.
If you have any doubts and you have a better way, please contact us.
Some customers will ask us if we want to place entire sheet dome array on PCB panel at one time, in order to save time and assembly cost, is it possible? How to place it and what we should do?
Today I’d like to share some basic information for that. Firstly we need to know the structure of dome array, please see below two structures: one sheet dome array placing and single dome array placing, you could see there is only a little difference between them, add one more layer transfer film.
It’s very simple to assemble entire sheet dome array on PCB panel at one time, same as placing single dome array at one time, just one more step and here are some basic steps:
1) Clear the PCB, make sure there’s no dirt, dust, or any other contamination;
3)Put entire sheet dome array on PCB panel by manual.
4)Press surface of dome array to make sure it adhere on PCB firmly, then peal off the transfer film from top side.
5)Finished the assembly.
Please note the bonding force of glue will become more and more stronger after about 24 hours, without any movement, pressure, etc. It means if after 24 hours, you cannot peel off dome array from the PCB, without damage the dome array, because the peel strength at that time will be extreme big comparing to initial value.
And in order that you could understand more clearly about it, we take a video about it, please see below video for details.
I think you will have another question, whether only this way could place one sheet dome array at one time? The answer is no. I will share another method to you in next article, please Stay tuned for more news about us.
For some metal domes, they sounds crispy when pressing them, while others not. Then what plays the role during the process? Now let me introduce it to you.
Virtually, there is a calculation method, which is, using the value after trip force minus rebound force to divide the trip force, then we will get the hand feeling percent of metal domes. The hand feeling percent value is generally 50%(±15%). The larger the percent, the louder the sound and vice versa. However, the hand feeling percent can not surpass 70%, as a general rule. This is because, the rebound force will get less if the hand feeling percent is too large. It is easy to make metal domes concave if pressing for a long time.
At Best Technology, customers can order metal domes with different hand feeling percent, according to the different applications of products.
If you have any queries, comments or suggestions, welcome to contact us.
We are pleased to announce that Best Technology has recently completed 14 years of its glorious journey. Every step is worthy of being celebrated. On June 26, 2020, our founder, Peter, Emily, group leaders and all the employees spent this unforgettable festival together.
On Best Technology successful journey, Peter emphasized- “The past 14 years have been a period of growth and a learning experience for us as we went through several trials and errors till we deliver successful business. Today we are proud of the fact that our employees can make great progress day by day after training with us and feel confident taking on tough project-related challenges,many thanks for all the endeavour from employees and thanks for the great support from our suppliers and customers. Best Technology’s continuous development can not do without them.”
We have come a long way from 2006 when we started off with just 1 people(Peter). Today we are proud to announce that we have nearly 100 employees and many sister companies spread all over China mainland and also have customers in over 150 countries around the world.
From above, it is evident that there has been a staggering growth in the number of employees in the span of 14 years. This enhanced employee strength has built the roadmap to Best Technology’s success.
The above graph presents our company’s growth against the years 2006 to 2020. It can be seen that the growth rate is very high from 2006($8000) to 2019($6560,000). At this year 2020, Best Technology still keeps growing with increasing sales volume in spite of COVID-19 outbreak.
Best Technology’s unique journey has been a brick-by-brick progress and has entailed years of efforts. Our company’s commitment in becoming world class distinctive solution of printed circuit board and metal domes in 2025 has paved the way to the series of milestones achieved. These are equally appreciated by the correct leadership of our chairman, Peter.
The primary aim of our company has been to equip the professionals with all possible accoutrements to tackle on-job challenges. Today’s ever changing face of businesses demands deeper knowledge, quality, and on-time delivery. Customers are always looking out for continuous and improved delivery. The best means to achieve the same is to keep improving.
We will continue our journey towards innovating the new ways of learning, delivering excellence to the customers and lending a hand to achieve professional goals.
What’s more, Best Technology’s 14th-year anniversary celebration is a solemn procession of efforts and dedication of the trainers and staffs who have spent their quality time to provide the best services and meet more expectations of the ever evolving PCB world.