Precautions for purchase of contact angle tester
- Source: Unknown
- Date: April 28, 2020
- Number of views: two hundred and twenty-five
The key to purchase the contact angle tester is to see the customer's application. We suggest customers to consider the following aspects when making specific purchases:
1. Purchasing summary of contact angle tester
Combined with our industry experience, we think that the selection and purchase of contact angle instrument can generally start from the following aspects.
First, what testing purposes do you want to accomplish? What is the size and shape of your sample?
Secondly, what contact angle testing techniques do you know? You may have a basic grasp of these technologies through the following statements.
Third, do you know suppliers well?
2. Requirements for use and accuracy of contact angle tester
The accuracy of the contact angle tester cannot be generalized. The contact angle tester with different methods has different accuracy. As described above, contact angle measuring instruments of different methods have their own purposes and accuracy. The key is to depend on the specific application needs of customers. But generally speaking, the accuracy of the contact angle measuring instrument is mainly reflected in the number of effective pixels, the design rationality of the optical system of the contact angle measuring instrument and other aspects. It is suggested that the customer can test some samples before deciding which contact angle measuring instrument to purchase.
At the same time, because the host design of the contact angle tester is not suitable for all samples, you must take into account your samples themselves. For example:
(1) The size of your sample. Sometimes, large samples are not suitable for the standard equipment of the contact angle measuring instrument. You must remember to talk with your supplier about your sample size, including size, thickness, etc. If the oil system tests the contact angle value of the core, you must communicate with the supplier. The sample table of the common contact angle measuring instrument cannot be supported.
(2) The shape of your sample. The measured contact angle is usually affected by the shape of your sample. If your sample is a curved surface, you usually need to correct the curved surface. If your sample is a cup shaped inner hole, you can only purchase the professional technology provided by Shenzhen Dongyi Seiko. No company in the world has mastered this technology. At the same time, the combination of curve and horizontal line technology can solve many problems.
3. Talking about the purchase of contact angle measuring instrument from the composition of contact angle measuring instrument
First, it is necessary to describe the system structure of the image analysis contact angle measuring instrument:
1. Optical system: the standard components are CCD camera, micro lens and video capture card.
(1) Based on whether you need to test the contact angle value that changes with time, you should consider whether you need a high-speed camera
Generally, the standard configuration of the contact angle tester is 25 frames/second. According to the application requirements of dynamic contact angle, the number of pictures captured per second can be increased, such as 100 frames/second. Among the imported instruments, some manufacturers have proposed 50 frames/second. In fact, this is a hardware dual buffer technology. From the practical technical point of view, it is a different concept from continuous shooting. If you want to buy a high-speed camera, we think the real speed is better.
Generally speaking, the best time for measuring the contact angle is 20 seconds after the drop is dropped. Basically, the contact angle tends to be stable at this time (contact angle hysteresis or water absorption). However, if your sample is highly absorbent (such as paper diapers), we strongly recommend that you purchase high-speed cameras.
Usually these need to be discussed with the supplier. They will recommend a camera suitable for you according to your different needs.
(2) Lens: The lens usually meets the requirements. However, it is not ruled out that some domestic instrument manufacturers are not aware of optics and write the magnification at will, which is quite irresponsible. You can ask the supplier to provide the magnification of mm represented by each pixel. This is easy for professional manufacturers to give.
(3) Light source: This is very critical. In fact, the light source is very particular about the imaging effect. However, we insist that as core secrets are involved, please contact our professional engineers of Dongyi Seiko for detailed technology.
(4) Video capture equipment: the current contact angle instrument is usually equipped with a video capture card, which puts forward a quite high requirement for the computer system. Obviously, it must be plugged into the computer, so users are required to install hardware. In our opinion, it is better to use USB or 1394 port video devices. After all, it is just a matter of increasing costs, but for users, it is more than convenient.
2. Injector system:
There are three kinds of standard micro samplers, peristaltic pumps and syringe pumps. The syringe pump is equivalent to an automatic micro propulsion system and a micro injector.
The current injection technology is generally in line with the requirements. However, if you have a high precision requirement, you may choose a software controlled injection system, which will be more convenient and the injection precision control is better.
3. Main frame design:
The main considerations are: what functions are required and what precision is required. You can discuss it with the supplier. It is worth pointing out that foreign instruments are not necessarily the best. For example, we think that the stability of the KSV rack is poor and the operation is inconvenient. We think that the precision of KRUSS is not enough, and the error of fine steel is relatively large.
4. Software system: This is the key of the contact angle instrument. It mainly includes video capture, image capture, image analysis and contact angle data application.
This will involve contact angle calculation technology and surface free energy analysis technology. We believe that good software is usually easy to upgrade and operate. When you don't know about the contact angle meter, you can talk more with your supplier and see whether your supplier meets the requirements.
