School of Engineering Engineering ScienceSystem ModellingControl (1SMC)Control System of anEngraving Machine SMC Assignment ReportAY 2017/2018, OctoberSemester Date of Submission: 4 June 2017 Report By: Aaron Oon Wei Yan Student Number: S10166387G Supervisors: Mr Lee Yong Him Tutorial Group: P3C2 Diploma: Engineering Science Year 3 Introduction Engraving is the act of incising a design onto a solid, typically flatsurface by cutting grooves into them. When materials like silver, gold, orsteel are engraved, the result may be a decorated object. It may also act as anintaglio printing plate when copper or another metal is used. Engraving has been a historically important methodology for producingimages on paper for artistic and mapmaking purposes, and for commercial usageand illustrations for books and magazines. However, this traditional method haslong been replaced by various photographic processes in its commercialapplications. This is partly due to the difficulty and intricacy of thetechnique.
Burin engraving, or engraving with the use of machines, continues to bepracticed by multiple professions such as goldsmiths, glass engravers, gunsmiths and many others. In contrast, modern design-incisingtechniques such as photoengraving and laser engravingare continuously improved in terms of accuracy, affordability and portabilitywith systems such as the control system. In this report, we will be goingin-depth about the position control system of an engraving machine, morespecifically, a laser engraving machine. Methods of Engraving When it comes to engraving equipment, consumers have 2choices – rotary engraving machines or laser engraving machines. The preferredmethod depends on the desired result,durability, and the materials to be engraved. The durability and depth of thedesign are the most important factors for consideration For metals or plastic materials, or foroddly-shaped items and objects requiring permanent engravement, rotaryengraving machines make better engraving equipment solutions.
The reasons areelaborated belowIf the material is metal, rotary engraving machines willprovide a greater depth that is notachievable with a laser. Additionally, if the material is plastic, a rotaryengraving machine can easily cut the material. Lasers are economicallydisadvantageous because they are required to have multiple filters to eliminatetoxic fumes. The shape of the item is also another factor for consideration.Rotary engraving machines can produce excellent results on uneven surfaceswhile lasers only perform well on flat surfaces. Last but not least, if thedurability of the component to be engraved is important to the buyer, therotary system is preferred. The rotary engraving process provides a moredurable and permanent finished product.
Rotary EngravingMachinesRotary engraving machines etch the surface of the materialwith tools that are fixated in a rotating spindle. The cutting tool eliminatesthe material from the surface to create the engravementRotary engraving is overall cheaper and requires lessmaintenance. This is because of its simplicity as compared to itstechnologically advanced laser counterparts, which require specializedknowledge to operate and maintain the equipment.
Laser Engraving Machines Laser engraving is asubset of laser marking. It is the act of employing lasersto engravean object. The technique does not need inks, nor does it involve mechanicalengraving instruments that will wear over time. Laser engraving has its advantages because of itsability to engrave a wider variety of materials as compared to rotaryengraving.
The laser provides an extremely high quality engravement inmaterials such as wood and trophy plaques and is also able to generatephotographic images of a number of materials. Laser engraving equipment employslaser power focused through multiple mirrors and lenses to etch parts. Here are some otheradvantages of laser engraving:? It is a permanent identification methodthat cannot be modified? It does not require consumables whichreduces cost ? It is environment-friendly with feweremissions This report focuses on the modeling and analysis ofthe laser engraving machines. Laser EngravingMachines Physical ArrangementThe laser engraving machine can be broken down intothree main parts: a laser, a controller, and a surface. The laser emits thebeam which removes matter from the object, allowing the controller to etch theintended design on the object.
The direction, intensity, speed and laser beamspread is controlled by the controller. The surface is picked to match what thelaser can act on. The figure below shows a laser engraving machine Figure 1: Laser engraving machine Control Figure 2: Control schematic of laserengraving machine 1 Applications Laser engraving is one of the mostvastly employed processes in the manufacturing world. It can be found acrossvarious industries such as the aerospace, automotive, electronics, semiconductor and medical sectors. It is evident that it’s clear that the possibilities for laser cutting is endless.Listed below are some applicationsfor laser engraving:? Laptop engravement? Glass engravement? Textile engravement? And many more However, with its many advantages comes along manydisadvantages as well.
It is limited to thetwo-dimensional plane of the x-y direction scan. Metals with high hardness andlow ignition point cannot be used as the material to be engraved. For example:ceramic, glass, wood, iron, and copper.
Analysis of LaserEngraving Machine Control SystemThe movement of a laser engraving machine is operatedusing a closed loop control. The transfer function of a typical laser engravingmachine is as follows:With these estimated parameter values, the transfer function of the laserengraving machine is as follows: AnalysisCOMSOL was employed to simulate a dynamic thermal rayover different materials. With interaction modeling of various materials withthe laser beam, the temperature distribution was produced. The temperature isthe main parameter to finding out the geometry of an engravement. As the laserheats up the material and the temperature passes the vaporization temperatureat high power intensity, the density of the material would take up the densityof air to form the engravement. (a) Sensitivity ofclosed-loop system to changes in the actuator constant ? 2COMSOL was used to generate the output responses(above figure) for ? = 0.2 (red curve) and ? = 0.5 (green curve) and ? = 0.
8 (blue curve)respectively. From the response curves it can be concluded that with increasein ?,the output tracks the input more closely. However, the response oscillatesmore. By introducing derivative control action, the system damping can beimproved. Conclusion 1.
This report introduces both modern forms of engraving machines. Wecompared the differences, advantages and disadvantages of the rotary engravingmachine and the laser engraving machine. 2. The focus of the study is on the modeling and evaluation of theclosed-loop laser engraving machine control system. The analysis was carriedout and the results are produced using COMSOL. 3.
Given the analysis andsimulation results, it can be concluded that as the actuator gain ? increases, the system becomesmore responsive to the input commands and the disturbance rejection improves. References 1 Dongyun, W., & Xinpiao, Y.(2014, March 18). An Embedded Laser Marking Controller Based on ARM and FPGAProcessors. Retrieved January 22, 2018, from https://www.hindawi.com/journals/tswj/2014/716046/ 2 Karbasi, H.
(n.d.). COMSOLAssisted Simulation of Laser Engraving .
Retrieved January 23, 2018, from https://www.comsol.com/paper/download/62352/karbasi_paper.pdf