The nPoint Design Process
First it is best to look through nPoint’s current nanopositioning piezo stage listing to determine if a current design is the best fit. A system can be tested on a trial basis to verify if it meets the application requirements. If it does, other factors, including controller integration, will be considered in the next steps in the process. When a custom design is required, a set of specifications are necessary for the initial design phase.
Example Specifications for Initial Design Phase
- Scan Speed – How fast the system needs to move either by scan rate or step and settle time.
- Load Mass and Shape – Determines how fast the stage can scan by modeling the lowest system resonance of the loaded piezo stage. 3D models are helpful in accurately modeling this condition.
- Travel Range – The necessary travel of the stage. Piezo flexure stages are typically limited to a travel range of 2mm.
- Stage Weight – The maximum mass of the piezo stage.
- Stage Material – Materials of which the stage can be machined. Examples include: aluminum, titanium, and stainless steel.
- Environment Operating Conditions – such as UHV, varied temperature, or rugged external environments
- Resolution and Accuracy – Define precision, accuracy, and step size requirements. Determine what sensors are necessary for closed-loop control or if open-loop control is adequate.
nPoint will then design and model the piezo stage using FEA. A design proposal will include the expected specifications of the system under approved design characteristics. Possible improvements and trade-offs for making changes to the system will then be discussed.
Example Custom Design Using FEA
Once the stage has been designed the next step is to build a prototype for testing. Single or multiple prototype systems can be built depending on the customer’s requirements. nPoint will characterize each stage and share the results with the customer when the first prototype ships. Testing can then be done by the user on site. Following onsite testing, nPoint will meet with the user to determine how the system performed in the specific application. Any changes, adjustments, or redesigns can then be performed for further development.
nPoint offers a variety of controller designs. The most commonly used design is a closed-loop controller. Each axis of the piezo stage requires a channel for the controller. For example, a single channel controller would be mated with a single axis stage, while a three channel controller would be required to run a three axis stage.
Controllers can be fully enclosed or be sold as PCB boards with the same functionality. Custom enclosures featuring your company’s graphics are also an option. nPoint features digital controllers, which allows great flexibility for interface and software options. Custom firmware can be written for applications to further integrate other systems into the controller.
Example OEM Controller Board
System Interface Options
- Analog – Standard Analog interface via BNC connectors. -10V to 10V, 0 to 10V, or other settings can easily be programmed.
- USB – LabView and DLL drivers facilitate the integration of nPoint systems. A variety of programming languages can be used.
- Digital I/O – The user can assign different triggering functions to the 9-pin digital interface.
- High Speed Parallel Interface – Offers communication with the controller at full loop speed, which allows the user to set and read position commands every 24 microseconds at 20-bit resolution
- PFM Interface – Designed to receive position commands in real time while facilitating integration of industry standard motion controllers.
- Ethernet Interface – Offers full functionality of the standard USB interface over a greater distance.
- Digital Encoder Interface – Enables integration of a quadrature encoder, which allows the use of external sensors with nPoint controllers for full closed-loop piezo positioning.
- AFM Interface – Designed to integrate into commercial AFMs to provided closed-loop scanning.
- Custom – Ask our team of engineers about other interface options.
PC based software nPControl is standard with all nPoint controllers. nPControl offers control-loop tuning, high resolution position recording, waveform generation, trajectory generation, and raster scanning. nPoint can provide custom software development to best fit your application. Current software compatibility includes:
- Nikon Elements
Click to explore examples of nanopositioner applications.