Off-line programming and simulation for 2-axis wire EDM

U radu je predstavljena metodologija za uspostavljanje off-line sistema za programiranje sa verifikacijom putanje alata i simulacijom koja uključuje vizuelizaciju procesa obrade, orijentaciju pribora i pomeranja mašine. Ova metodologija je opisana pomoću IDEF0 dijagrama i razrađena pomoću PTC Creo CAD/CAM sistema. U radu je prikazan modelirani detaljni virtuelni prototip mašine Evis, sa definisanim svim kinematičkim vezama između pokretnih delova, kako bi bilo moguće uključiti virtuelni model mašine u simulaciju. Off-line programiranje omogućava višestruku verifikaciju programa, posle koje se program može odmah izvršavati na mašini. Off-line programiranje je verifikovano na realnom primeru verifikacijom i izvršenjem programa za njegovu obradu.This paper presents a methodology for establishing off-line programming system with toolpath verification and simulation including visualization of the machining process, fixture orientation and machine movements. This methodology is described using IDEF0 diagrams and is elaborated by using PTC Creo CAD/CAM system. This paper describes modeled detailed virtual prototype of WEDM machine Ewis, with all kinematic relationships between moving components being defined, with the aim to include virtual machine model in machine simulation. Off-line programming allows immediate execution on the machine of multiple verification programs after verification. Therefore, the off-line programming is verified using the real example and its program verification and execution

Off-line programming and simulation for 2-axis wire EDM

U radu je predstavljena metodologija za uspostavljanje off-line sistema za programiranje sa verifikacijom putanje alata i simulacijom koja uključuje vizuelizaciju procesa obrade, orijentaciju pribora i pomeranja mašine. Ova metodologija je opisana pomoću IDEF0 dijagrama i razrađena pomoću PTC Creo CAD/CAM sistema. U radu je prikazan modelirani detaljni virtuelni prototip mašine Evis, sa definisanim svim kinematičkim vezama između pokretnih delova, kako bi bilo moguće uključiti virtuelni model mašine u simulaciju. Off-line programiranje omogućava višestruku verifikaciju programa, posle koje se program može odmah izvršavati na mašini. Off-line programiranje je verifikovano na realnom primeru verifikacijom i izvršenjem programa za njegovu obradu.This paper presents a methodology for establishing off-line programming system with toolpath verification and simulation including visualization of the machining process, fixture orientation and machine movements. This methodology is described using IDEF0 diagrams and is elaborated by using PTC Creo CAD/CAM system. This paper describes modeled detailed virtual prototype of WEDM machine Ewis, with all kinematic relationships between moving components being defined, with the aim to include virtual machine model in machine simulation. Off-line programming allows immediate execution on the machine of multiple verification programs after verification. Therefore, the off-line programming is verified using the real example and its program verification and execution

Prediction of thrust force and torque in tapping operations using computer simulation

Pristup opšte mehanike rezanja, uspešno je primenjivan za različite zahvate obrade alatima složene geometrije. Ovde je primenjen za predviđanje aksijalne sile i momenta pri urezivanju navoja mašinskim ureznikom. Osnovna ideja je da se podaci određeni kroz testove sa ortogonalnim rezanjem i izrazi za sile pri kosom rezanju iskoriste za određivanje komponenti sila rezanja na diskretizovanim delovima sečiva. Razvijeni program za simulaciju izračunava trenutnu poziciju ureznika u odnosu na rupu, presek nedeformisane strugotine za svaki zub. Integracijom po svim zubima u zahvatu dobijaju se trenutne vrednosti momenta i aksijalne sile za svaki simulacioni korak u ukupnom ciklusu urezivanja navoja.General cutting mechanics approach, successfully used for different machining operations using cutting tool with complex geometry, was here applied for prediction of cutting forces in tapping with machine taps. Basic idea was to exploit data obtained from orthogonal cutting tests and relations for oblique cutting forces to obtain force components on discretized parts cutting edges. Developed simulation program calculates instantaneous positions of tap in hole and un deformed chip area of each engaged tooth. Integration along all engaged teeth provides actual values of torque and thrust force in every simulation step in the whole tapping cycle

Recognition of Planar Segments in Point Cloud Based on Wavelet Transform

Within industrial automation systems, three-dimensional (3-D) vision provides very useful feedback information in autonomous operation of various manufacturing equipment (e.g., industrial robots, material handling devices, assembly systems, and machine tools). The hardware performance in contemporary 3-D scanning devices is suitable for online utilization. However, the bottleneck is the lack of real-time algorithms for recognition of geometric primitives (e.g., planes and natural quadrics) from a scanned point cloud. One of the most important and the most frequent geometric primitive in various engineering tasks is plane. In this paper, we propose a new fast one-pass algorithm for recognition (segmentation and fitting) of planar segments from a point cloud. To effectively segment planar regions, we exploit the orthonormality of certain wavelets to polynomial function, as well as their sensitivity to abrupt changes. After segmentation of planar regions, we estimate the parameters of corresponding planes using standard fitting procedures. For point cloud structuring, a z-buffer algorithm with mesh triangles representation in barycentric coordinates is employed. The proposed recognition method is tested and experimentally validated in several real-world case studies

Converting of virtual machine from different CAD/CAD environments and its configuring in desired environment

Ovaj rad opisuje konverziju virtuelne mašine iz različitih CAD/CAM okruženja i njeno konfigurisanje u izabranom okruženju, što se često javlja kao potreba kada je potrebno simulirati rad određene mašine. U ovom slučaju razmatraju se dva CAD/CAM okruženja, i to Cimatron i Creo. Razmatrana je mogućnost prenosa željene virtuelne mašine iz Cimatron CAD/CAM sistema i njenog pretvaranja u adekvatnu virtuelnu mašinu u PTC Creo okruženju, uz primer identične simulacije u oba okruženja. Prenete datoteke virtuelne mašine se konfigurišu u softverskom okruženju PTC Creo i STEP-NC Machine. Nakon konfigurisanja virtuelne mašine izvršena je simulacija mašine u pomenutim softverskim okruženjima.This paper describes the conversion of a virtual machine from different CAD/CAD environments and its configuring in the desired environment, which often arises as a need when you want to simulate the operation of a specific machine. In this case, two CAD/CAM environments are considered, namely Cimatron and Creo. The possibility of transfer the desired virtual machine from Cimatron CAD/CAM system and its converting to PTC Creo is considered, with an example of identical simulation in both environments. The transferred files of virtual machine are configured in the PTC Creo and STEP-NC Machine software environments. After configuring the virtual machine, the machine simulation was performed in the mentioned software environments

Contemporary approach to the design of circular form tools for complex-geometry part manufacture

Primena profilnih strugarskih noževa u industriji prisutna je unazad nekoliko decenija. Upotreba profilnih noževa u industriji je u ekspanziji, a ovu sve veću popularnost mogu pripisati smanjenju troškova proizvodnje i uštede vremena obrade. Sa druge strane, jedan od glavnih nedostataka predstavlja sam metod njihovog projektovanja. Ovaj nedostatak se ogleda kroz ograničenost obrade pravolinijskih i lučnih segmenata izratka. Grudni ugao za svaki segment ima različitu vrednost, što predstavlja dodatno ograničenje. U slučaju da je neophodna primena profilnih noževa za izradu delova složene geometrije, vrednost grudnog ugla zahtevala bi da bude nula. U ovom radu predstavljen je savremen način projektovanja kružnih profilnih noževa primenom CAD sistema. Na ovaj način, ne samo da se obezbeđuje konstantna vrednost grudnog ugla duž celog sečiva koja može biti i različita od nule, već se obezbeđuje i optimalna geometrija alata za obradu željenog materijala. Dodatno je izvršena i eksperimentalna provera geometrije profilnog noža projektovanog uz pomoć nove metode.Form tools have been used in industry for a number of decades. Their use is booming and such growing popularity can be attributed to minimized manufacturing costs and shorter manufacturing time. On the other side, one of the major drawbacks is the method of their design. It reflects in the constraints present in the machining of straight-line and circular arc segments of a workpiece. For each segment the rake angle has a different value, which imposes an additional constraint. In case it is necessary to use form tools to manufacture complex-geometry parts, the value of the rake angle would require to be zero. The paper presents contemporary design method of circular form tools by implementing CAD system. This way, it is not only provided a constant value of the rake angle across the entire cutting edge, which can be different from zero too, but also optimum tool geometry for machining a desired material. Additionally, the geometry of a form tool designed using a new method was experimentally tested

Detection of planar segments in point cloud using wavelet transform

In this paper we propose a new method for 3D plane segmentation and fitting from point cloud. The method is based on discrete wavelet transform. In particular, we exploit the sensitivity of certain wavelets to abrupt changes in the signal, as well as their orthonormality to linear functions to effectively recognize planar regions. The application of the proposed method is evaluated using two examples. The first example refers to a synthesized signal, and the second, real world example deals with the detection of the welding seam pose within adaptive control of robotized continuous welding

Polycrystalline Cubic Boron Nitride (PCBN) Tool Life and Wear in Turning of Amorphous-Crystalline Iron-Based Coatings

The paper presents PCBN-Ciborit cutting tools life and wear test results. The effects of the machining regime when turning amorphous-crystalline Fe80B20 and Fe79Cr16B5 coating systems applied to conventional workpiece materials were assessed. It has been shown that the observed tool wear mechanisms are complex in their character and are dominated by abrasive-mechanical, adhesive and chemical effects in the cutting zone. Under changing turning conditions tool life is affected by the structural-phase composition and by the non-homogeneous structure of the coating. Specifically, when turning gas-flame coatings deposited with a Fe80B20 electrode and electro-arc coatings with a Fe79Cr16B5 electrode the lowest wear and the highest tool life was achieved at cutting speeds of nu = 1.1 to 1.2 m/s and a back rake angle of gamma = -10 degrees It has been demonstrated that a change of the back rake angle from gamma = 0 to -10 degrees does not have a great effect on tool life contraty to the case with gamma = -20 degrees

Recognition of one class of quadrics from 3D point clouds

Within cyber physical production systems 3D vision as a source of information from real-world provides enormous possibilities. While the hardware of contemporary 3D scanners is characterized by high speed along with high resolution and accuracy, there is a lack of real-time online data processing algorithms that would give certain elements of intelligence to the sensory system. Critical elements of data processing software are efficient, real-time applicable methods for fully automatic recognition of high level geometric primitives from point cloud (surface segmentation and fitting). This paper presents a method for recognition of one class of quadrics from 3D point clouds, in particular for recognition of cylinders, elliptical cylinders and ellipsoids. The method is based on the properties of scatter matrix during direct least squares fitting of ellipsoids. Presented recognition procedure can be employed for segmentation of regions with G1 or higher continuity, and this is its comparative advantage to similar methods. The applicability of the method is illustrated and experimentally verified using two case studies. First case study refers to a synthesized, and the second to a real-world scanned point cloud

Recognition of one class of quadrics from 3D point clouds

Within cyber physical production systems 3D vision as a source of information from real-world provides enormous possibilities. While the hardware of contemporary 3D scanners is characterized by high speed along with high resolution and accuracy, there is a lack of real-time online data processing algorithms that would give certain elements of intelligence to the sensory system. Critical elements of data processing software are efficient, real-time applicable methods for fully automatic recognition of high level geometric primitives from point cloud (surface segmentation and fitting). This paper presents a method for recognition of one class of quadrics from 3D point clouds, in particular for recognition of cylinders, elliptical cylinders and ellipsoids. The method is based on the properties of scatter matrix during direct least squares fitting of ellipsoids. Presented recognition procedure can be employed for segmentation of regions with G1 or higher continuity, and this is its comparative advantage to similar methods. The applicability of the method is illustrated and experimentally verified using two case studies. First case study refers to a synthesized, and the second to a real-world scanned point cloud