MotoMaker: A robot FDM platform for multi-plane and 3D lattice structure printing

Additive manufacturing is a process to fabricate three-dimensional (3D) objects usually by joining a material layer by layer. The layer by layer joining process simplifies the fabrication method by slicing the 3D object into stacks of 2D contours. The layers are combined in a single build direction to form the 3D object. In this research, a six degrees of freedom robot arm is integrated with a fused deposition modeling system for multi-plane and 3D lattice structure printing applications. The integration processes in developing the platform are discussed including the robot arm platform, extruder system, software architecture, toolpath generation, 3D lattice generator, and extruder calibration. Use of the system offers unique advantages over a conventional Cartesian 3D printer platform which is limited to single-plane layering for the printing of 3D objects. Test cases are performed to demonstrate the capability of the robot arm fused deposition modeling platform for multi-plane object printing and 3D lattice structure printing

Rapid Fabrication of Glass Micro and Nanostructures via Laser-assisted Hot Embossing

The escalating demand for glass that exhibits various surface functions has encouraged efforts to develop more efficient and economical micro-/nano-patterning of glass substrates. We propose rapid hot embossing of glass micro-/nanostructures using an infrared transmissive mold assisted by CO2 laser irradiation. This resistless, etch-free technique utilizes the synergy of the silicon mold’s high transmittance and strong optical absorption of the glass at a 10.6-μm wavelength. Furthermore, this non-isothermal process requires preheating of the glass temperature below the glass transformation point (Tg) of the glass, eliminating the soaking time, and using a short contact pressing time and a lower pressing load to produce high-resolution space patterns. The method is capable of instantaneous high-resolution replication of various grating patterns from the nano- to microscale with a single laser scan. By controlling the scanning speed and ensuring sufficient pressure and heating depth on the glass surface, 250-nm to 50-μm line- widths and space patterns were embossed in a few seconds with excellent replication fidelity. The laser-assisted hot embossing methods developed in this study facil-itated high-throughput, energy-efficient, reproducible, and highly accurate micro-/nano-patterning of glass surfaces

Pressure based control for a variable speed diesel engine driven pump controller

Chemical cleaning is a process that utilizes chemical as a cleaning medium to remove unwanted contaminants. The chemical cleaning process may involve with the use of pump to circulate the chemical during cleaning process. The pump for the cleaning process can be driven by electrical or internal combustion engine. This paper presents the development of a variable speed diesel engine driven pump controller for chemical cleaning application. The controller utilize proportional control method as the control scheme. The variable speed diesel engine driven pump system includes a diesel engine coupled with centifugal pump, a controller, pressure sensor, and battery powerpacks. All the components are mounted on a skid platform for the ease of use as a system. Proportional control method were used in order to get the critical gain parameter to compute PID parameter gains using Ziegler Nichols tuning metho

Laser-assisted thermal imprinting of glass guided mode resonant (GMR) optical filter

Laser-assisted thermal imprinting of glass nanostructures is demonstrated. Compare to the existing thermal imprinting, this method significantly reduced the contact imprinting time. The quality of the replicated glass nanostructures revealed by field emission scanning electron microscope ( SEM) and atomic force microscope ( AFM) exhibited a very smooth surface finish that closely matched the profile of the silicon mold. As proof-of-concept, the utility of laser-assisted, imprinted glass nanostructures as guided-mode resonant (GMR ) optical filter was evaluated. The peak spectral values obtained were satisfactory; which yielded an average FWHM and PWV of 4.6 nm and 691.39 nm respectively

Rapid Direct Continuous Method for Hot Embossing of Glass Microlens Array Combined with CO2 Laser Irradiation and External Preheating/Cooling

Hot embossing of glass micro structures requires long thermal cycle, generally takes no less than 15 min due to the isothermal heating, pressing and cooling performed inside a closed vacuum chamber. In this paper, a new hot embossing procedure was presented. First, the glass was preheated slightly below its glass transition temperature at the heating station. Then, a thin layer of the glass surface was further raised to high temperature temporarily through CO2 laser irradiation. The glass was then quickly transferred to the embossing station for pattern transfer, demolding and followed by external cooling. This method accelerated the filling of glass material into the microlens array mold cavities and outperforms the conventional method in terms of overall cycle time reduction, lower mold working temperature and embossing pressure. Microlens array with diameter of 135 µm, sag height of 18.5 µm and pitch of 200 µm were faithfully embossed onto the K-PG375 optical glass time in a time scale of about ~3 s. Optical evaluation of the glass MLA was also performed using charge couple device (CCD) camera which showed uniform spot intensity

Feasibility Study of Wafer Scale Laser Assisted Thermal Imprinting of Glass Nanostructures

Major challenges for any direct nanostructuring method on glass substrate is the difficulty to scale up the patterning area to industrial scale. In this work, a rapid and large area direct thermal imprinting of glass nanostructures using silicon mold assisted by CO2 laser irradiation was demonstrated. Pattern transfer was successful for experiment trial of one spot laser irradiation and laser scanning with imprinting area of 100 mm2 and 400 mm2; confirmed by SEM and AFM measurement. When the method was extended to a larger imprinting area (2000 mm2), the glass was cracked and partially imprinted due to the high cooling rate of the glass after laser irradiation and misalignment of the glass during the contact pressing step in our molding setup

Development of an image rotary encoder for motion control

A rotary encoder reads rotational motion (angular position and speed) and converts the motion into electrical signals. It involves two components: a designed coded-disc to represents rotational information and a sensor to convert the coded information into electrical signals. A conventional rotary encoder uses three major elements, a pattern code disc, a light source and a photo-detector. Factors affecting rotary encoder are mechanical component alignments, resolution enhancement, size reduction, additional processing electronics and the working environment. Depending on the design of the coded-disc and the signal interpolation, a rotary encoder can function as an absolute or incremental encoder. An absolute encoder can determine the angular position without the need to have a reference position. On the other hand, an incremental encoder requires a reference position in order to determine the angular position. In operations, when an incremental encoder is started, the system has to move to the home position in order to set a reference point. An absolute encoder does not require home operations because it knows exactly the current angular position. As such, an incremental encoder requires an additional power supply when the system is turn-off so that it can “memorize” the current position. An absolute encoder is more expensive and the angular position range is limited by the disc size. Many researchers proposed and implemented different alternatives to absolute encoder. One technique is using an image rotary encoder. Current trends in digital image processing techniques have been applied widely into various applications. Some of the applications emerge as a sensing device with the assist of digital image processing techniques. Therefore, the research objective is to develop an image rotary encoder based on image texture before converting it into speed and motion data. The image texture is captured from a specially-designed texture of rotating disc using a digital image sensor. The proposed image rotary encoder is based on pixel changes by motion of rotating disc. The captured images are then converted into motion data by an image processing algorithm. The output signal is a binary position code which is similar to the conventional absolute rotary encoder. Performance of the image rotary encoder is validated by comparing the speed and position with the conventional rotary encoder. Experimental results indicate that the speed and position measured by the developed image rotary encoder are directly proportional to those measured using the conventional rotary encoder. Experiments also confirmed that the developed image rotary encoder can be utilized as a feedback device to a DC motor PID position control. Therefore, the developed image rotary encoder successfully functions as an absolute rotary encoder

Small cleaning robot for office window

Cleaning window for the office building is one of the important aspects in building maintenance activities which has been carried out regularly. The cleaning jobs are done by human might involve high risk. This project focuses on the development of a small cleaning robot for office window to substitute human force in window cleaning. The robot needs to satisfy certain criteria that are; portable, small size, lightweight,automatically operated and can clean all the corner of the windowpane. This robot is operated by suction cup with vacuum pump as the adhering mechanism and two wheels for the locomotion mechanism. The small amount of liquid is injected in between suction pad and glass surface to reduce the friction while operating. The body is made from acrylic to minimize weight of the robot. The robot is programmed using microcontroller and based on the window pane size. The application of the robot in the real world is hoped to help humans and reduce cost in office window cleaning activities

Bar Code Detection Using Omnidirectional Vision for Automated Guided Vehicle Navigation

In this paper, a study on detectability and readability of barcodes using omnidirectional vision system for automated guided vehicle is presented. Images from omnidirectional camera are known to be distorted against the height of the object. We present an algorithm for detecting and reading barcodes successfully without correcting the image distortion. Experiments were conducted both when the AGV was in motion and at rest. Three contributing factors were identified for successful barcodes detection and reading