Computer Integrated Manufacturing
This week the CIM class returned to the traditional education model – we took final exams. As the classes are predominantly seniors, we had all students take both the online exam created and administered by Project Lead the Way and also the exam that has been created specific to the CIM class and some of the additional curriculum we have studied this term along with projects we have worked on. One part of the exams included writing a program in ROBOPro that demonstrated understanding of open and closed loop control systems. Generally speaking based on the results of the exams students did demonstrate a broad understanding of the curriculum material this term, which is an indication that the class was successful.
Outside of taking exams, some students have also been working on independent projects. Several students have been using the cnc plasma torch to cut designs out of mild steel. Other students have finished small and larger projects that integrated parts made on the cnc mills, laser engraver and the 3D printer. That students are able to effectively use all of these machines on their own with unique designs of their own making is another verification that this has been a successful class.
With this week of finals, we will no longer have any seniors in the class. The juniors will be working on some special projects next week and we might be able to squeeze in another field trip. I have appreciated all of the dedicated effort of all students this year and look forward to hearing about their activities as they either transition into college or return for their senior year. I would also like to express my appreciation to all of our parents for their support this term.
To conclude our coursework for the semester students worked on the last project that involved integration of a robot with a model transport system. As was the case with the freight elevator project, the assignment was presented as a request for quotation with a bid invitation letter, an abbreviated performance specification and an evaluation matrix. The project was to include an elevated long unsupported span of conveyor, lift and drop sections, turntables, conveyors and/or shuttles and an automated storage and retrieval machine. The ultimate customer for this exercise was Disney and the purpose was to create a model of a distribution system to handle merchandise for three of Disney’s characters – Snow White, Buzz Lightyear and Mr. Toad. The system was to be able to run batches of six parts through the AS/RS and deliver them to three pick up points. The added feature of the project was to incorporate a Lynxmotion robot to interface with the Fischertechnik equipment to load the system.
Because this was an open ended design based on a performance specification, solutions that the three teams of students (or “companies”) varied widely. Vertical storage for the AS/RS application was used by one group and dual rail gantry type cranes were used by others. Pneumatic devices, a requirement of the project, were used either for gripping or as transfer pushers. This project stretched the capabilities of the modeling equipment but also gave the students a good feel for the complexities in a true integrated manufacturing (or in this case distribution) system.
To close out the week, we covered a unit on power calculations and also some summary items about types of computer integrated manufacturing systems including mass production, work cells and flexible manufacturing systems (FMS) that can be characterized as lights out factories in the most sophisticated applications.
From this point forward we will be concentrating on preparing for both the PLTW final examination and the class final examination. Both exams will be administered next week prior to senior graduation.
Students successfully completed their first Fischertechnik and ROBOPro project which involved designing a model of a freight elevator. After reviewing technical specifications from an actual client and project in the energy field, students were given an abbreviated bid invitation letter, performance specification document and a bid evaluation matrix. The students formed five “companies” and competed to submit the highest rated bid. I model of their proposed freight elevator was created as a part of this project. One of the requirements was to prepare a cost estimate for an actual freight elevator. As an aid in determining how to come up with an estimate we used the elevator at CAPS as a reference and identified the major elements of the elevator – structural frame, moving carriage, drive assembly, electrical control panels and engineering. We then made rough calculations as to drive sizes and the cost of fabrication to determine and approximate cost. This project was an attempt to model an actual engineering bid starting with technical specifications through actual pricing. The actual models that the students proposed and constructed ranged from simple two post lifts to quad post lifts with integrated moving doors.
The next project that students are currently working on is similar to the elevator project in that there is a request for bid, technical specifications and the requirement to build a working model of the proposed system. The theme of this project is to propose a distribution system for Disney. The bid is to include conveyors, and automatic storage and retrieval system, turntables, lift sections and interface with a pick and place robot. The “companies” for this project are larger due to the complexity. The control systems to have all of the components work automatically without manual intervention will be complex. This will be the last major project for students before we cover a unit on basic power calculations and then prepare for the final examination.
One other item of note was that the afternoon class was able to visit Ryerson this week. Ryerson is a major distributor and 1st stage processor of steel plate, coils and beams to industry. During our visit students were able to see how 20 ton coils are handled within the plant, unrolled and flattened and then either slit into narrower sheets or cut into large plates. This was a great example for students to see mechanical, civil and manufacturing engineering processes in a very heavy duty industrial environment.
This week marks the start of our work with Fischertechnik equipment and ROBOPro software. Students began by creating a beam with a shuttle device and writing a simple program to cycle back and forth 10 times first by using just timers and then by using an analog photo resistor on one end and a digital phototransistor on the other end to stop and reverse the motion of the shuttle. The application using timers is a closed loop system while the application using the fixed sensors is a closed loop system. Students observed that the open loop system allowed the shuttle to drift after a number of cycles while the closed loop system repeatedly reversed at the same points. We discussed applications for open and closed loop controls in industrial plants.
On Wednesday students from several engineering classes travelled to the old GM Leeds Assembly Plant to see a test unit for a van body transfer unit that will be installed at the GM Wentzville, MO plant later this summer. We met with mechanical and electrical engineers as well as installation supervisors to discuss the design and application of this transfer. Students were able to get a very close firsthand look at the complexities of an integrated control system with a number of different types of drive systems. Civil engineering students were able to examine the structure required to hold up a travelling unit weighing over 24,000 lbs. The electrical students were able to look through the ladder logic used with the AB Control Logix PLC units. This was a good field trip for students to see real world applications for several types of engineering.
Next week we will continue working with Fischertechnik equipment and ROBOPro on a design and build project for a prototype freight elevator application.
The majority of our time this week has been spent with students working on their competition project to produce a children’s pick and place puzzle. The requirements are that the puzzle contains a fixed base that has been designed in Inventor, tool paths applied in Mastercam and machined on one of the cnc mills. Entries have ranged from designs for shapes like trains, turtles, motorcycles and “Pac Man” or cartoon figures to a map of Europe. Most students have chosen to create their puzzle pieces on the laser engraver out of wood or plastic. Entries are currently being judged based on design originality, complexity, final part quality, marketability and conformance to the contest requirements (for example a minimum of 10 parts). The purpose behind this contest was to solidify students understanding of all of the parameters involved in designing and machining parts, including to correct set up, running and operation of the cnc machines.
Next week we will begin our last units working with Fischertechnik equipment and ROBOPro software. In these projects students will study open and closed loop circuits, analog and digital sensors and simulated automated work cells. We will also cover a unit on mechanical, electrical and pneumatic power as a part of these projects.
On Wednesday students from the CIM class and other engineering classes will be travelling to the old GM Leeds Assembly Plant to see a test unit for a van body transfer unit that will be installed at the GM Wentzville, MO plant later this summer. There will be mechanical and electrical engineers from Automatic Systems at the meeting to describe the steps they took in designing this complex piece of automation. This is a concise application of mechanical, civil and electrical engineering that hopefully will be very informative for students.
As we finish up working with RoboCell software students have divided up into teams to perform the handshaking operation between the Scorbot pick and place robot and the Intelitek mill. Students are using either a canned “Superman” logo for the milling operation or a design of their own choosing. The criteria with whatever design they are milling is that the system must load, mill and stack out a run of four identical parts. Variable programming is to be used for the final stack out of the parts. The key component of this exercise is to understand the wiring of the interlocks and to program in G&M codes the inputs and outputs for the Intelitek mill and in Scorbase the inputs and outputs for the Scorbot. The balance of the robot and milling programs is fairly straightforward. If the inputs and outputs are not correctly identified, in the wrong location in the program or missing bad things happen including collisions between the robot and the mill and having the robot drop parts in the wrong location. Students have demonstrated these features along with the instructor.
One other aspect of this handshaking exercise that equates to the real world is the failure of some of the functionality of the Scorbot and the mill. The mill abruptly changed identity and failed to operate for an extended period of time while the robot intermittently will skip lines of code in the program and for example fail to pick up a block of stock or fail to release the block when programmed to do so. We have been working to troubleshoot through those issues as would be the case in an industrial application.
As a review and final machining project students are competing with each other to produce a children’s pick and place puzzle that contains a fixed base and at least ten removable pieces. Their projects will be evaluated by independent judges with points awarded for design originality, design complexity, final part quality (fit and finish), marketability and conformance to requirements. These projects are to be completed by the middle of next week with final evaluation by the end of next week. The hope is to produce puzzles that might be of a high enough quality to be given to either pre-school classes or used for therapy.
Students have spent the majority of the week working on robot programming software for the Scorbot robot. We have gone through exercises learning how to use absolute and relative commands, circular commands to avoid interferences, variable programming (which is more efficient than recording line by line) and also how to program inputs and outputs to work with other machines. Students have tried out some of their programs on the Scorbot robot making adjustments for the height differential of the slide base on the Scorbot. By next week students will have created a program to run a sequence of four parts using the Scorbot and Intelitek Mill. The program will include variable programming and a palletizing element for the finished products.
We spent some time earlier in the week discussing the importance of the many types or material handling systems used in industry. It was noted that PLTW is especially high on ASRS, AGV’s and chain conveyors, but that with the development of controls technology and environmental influences other types of conveying systems including electrified monorails, skillet conveyors belt driven live roller conveyors and friction driven conveyors have gained popularity for their quietness, cleanliness (no oily chains) and economy.
Our scheduled trip to Unilever has been postponed, but hopefully will still occur before semester end. We will make a trip to Automatic Systems to witness a run off test for a body marriage transfer for a GM plant later this month.
With the completion of spring break we also have been winding down our work with our manufacturing unit. Students are still completing their projects including the children’s toy or puzzle, but are now starting to work on our next unit covering robotic applications for manufacturing industries.
We are starting to work with RoboCell software that is the same programming language used by our Scorbot pick and place robot. Students are working through a series of eight increasingly complex robot programs learning how to efficiently program movement to accomplish defined tasks such as basic movement to simulated processing in dip tanks to palletizing. As students complete some of the programs they are loading them into the Scorbot to verify that they are operating correctly. The culminating exercise will be for students to program the Scorbot to feed a run of four products into the Intelitek Mill and have the mill machine out a defined path in the part blank. This sequence is to be done automatically without manual intervention. The process is called “handshaking” and is a common interface between robots and automation in industry.
Next week students will continue to work on the RoboCell programs. At the end of the week we are planning a trip to visit the Unilever plant in New Century, KS to see how robots and automation are used in the food processing industry. There will be at least one robotic application using palletizing that will be a great example for students to see a real world application of the programs they are writing.
For most of this shortened week, students have been working on completing their assignments using all of the cnc machines in the classroom along with the laser engraver and the 3D printer. Students are demonstrating a greater understanding not only of the design parameters involved with cnc machining, but also the importance of considering tolerances and tool geometry. We are also learning the necessity to plan into the work how to secure parts to the milling table to avoid damage and provide full access to surfaces to be machined.
The highlight of this week was a field trip to Webco in Olathe. Webco specializes in close tolerance manufacturing of parts for companies like Caterpillar, Kenworth and Broaderson. They have very sophisticated automated laser cutting and plasma cutting tables, cnc press breaks, and multi-axis machining centers. Robotic welding work cells are also used for high volume complex repetitive welding tasks. Webco uses Inventor and Mastercam software for their design and cnc tool path layout software, which are the same packages we use in the CIM class, so it was a good application for students to see how the software we use is being applied in a manufacturing company.
In addition to seeing many of the machining and fabrication processes that we study in class on a large scale, the other important part of this learning experience was for students to learn about the management systems Webco has in place to efficiently track production and quality of their products. Webco is an ISO certified company that requires constant monitoring of quality measures and identification of continuous improvement opportunities. This system starts in the estimating stages and carries through engineering onto the factory floor. Progress towards achieving measured objectives is posted throughout the plant so employees can see how the company is doing. Concepts including lean manufacturing and just in time manufacturing are also a part of their process. Webco will be moving to a new facility with over double the floor space area of their current plant. It was very instructive for our students to talk with their managers on the details of how the new plant would be laid out for more efficient material process flow and also how they were going to migrate to the new facility over a series of months this summer and still maintain their scheduled manufacturing output.
After spring break, we will spend another week completing open projects and going over a few more lectures covering manufacturing processes before moving into the next phase of the class that involves robot programming and control systems.
Students are now working on a number of projects of their own design utilizing all of the cnc machines in the classroom as well as the laser engraver and the 3D printer. Our last assigned machining project before moving into the robotic programming side of the course is to design and build a children’s toy or puzzle that would be suitable for a designated age group. The goal is for students to pull together all of their knowledge to create a clean, finished design with a high level of complexity. To the degree that students are successful, we may want to try to find a home for the puzzle such as a day care center, school or a senior citizen center. Some students may choose to integrate metal and wood parts into their design and utilize their welding and cnc plasma torch cutting experience.
Because we fell a little behind with the snow days, we have been interjecting some traditional lecture material into several class periods this week. Topics have included a high level view of manufacturing processes, detailed processes for specific joining, separating and finishing operations and also an overview of the types of rapid prototyping machines available today. We are touching on processes such as forging, casting, water jet cutting, stamping and injection molding to name a few.
We will start off next week with a site visit to Webco, an Olathe based manufacturing company that specializes in close tolerance high volume precision parts for a variety of industries. Webco uses the same design and machining software that we use in the CIM class, so it will be a good opportunity for students to see how the software they are learning is used in industry. From a manufacturing standpoint students will get to see robotic welding operations, cnc metal laser cutting at very high speeds and volumes, cnc forming operations and multi-axis machining centers. This has always been an informative and enjoyable trip for students and we are very appreciative of Webco hosting us for these tours.
In between snow shoveling sessions we managed to accomplish some old and new items. Students have continue to work the lithophane and 4th axis milling projects as well as completing the documentation for the Tic Tac Toe project. Several students have been designing and creating on the cnc machines, laser engraver or the 3D printers additional projects using the knowledge they have gained of Inventor, Mastercam and the machine operating software. As this course has progressed over the last three years, it has been gratifying to see the increased level of complexity that students have included in some of their designs. They move quickly from basic concepts to machining some pretty intricate parts.
The main new curriculum for the class has been working with our welding equipment. Roy Croan, a certified welder and weld inspector with many years of experience has provided direct instruction to the classes in MIG and TIG welding of aluminum and mild steel. His instruction has covered both wire feed and stick welding using the two units in the metals lab. In addition to learning basic welding techniques some students have started working with the cnc plasma torch. Similar to using the cnc routers and mills, students begin with a CAD design and then apply toolpath settings for the plasma torch to follow. The parts are then cut out on the Torchmate plasma torch. As is the case with machining wood and aluminum on the other machines, we see that there is as much art as science with plasma cutting. Instead of speeds and feeds, we need to experiment with voltage settings, pierce heights and travel speeds to obtain higher quality cuts in terms of geometry and surface finish.
We will continue working with all of the equipment in the next two weeks. Several students will work on projects that combine wood and metal components, which again will bring into play the importance of tolerances. We are most grateful for the time that Mr. Croan spent with us helping to introduce the students to the world of welding.
Students are now working on multiple projects including finishing the Tic Tac Toe game, creating chess pieces on the 3D printer and two new projects using the Denford Mill. One of the Denford projects is to create a lithophane image on thin plastic material. The source material is a black and white image that is imported into Photo-V-Carve software. Settings for rough and finish cuts (maximum cut depth and intermediate depth cuts) are established and then the code is created by the software to directly load into the Denford Mill operating system. This is different from the standard machining we do using Inventor for the design and Mastercam for machining. The finished project at first appears to be a very rough machined piece of plastic, but when held up to the light the images looks very similar to a photograph.
The second Denford project is to create a three dimensional part that can be machined on the 4th axis fixture. This fixture is a trunion mount that rotates the parts in small degree increments while the milling bit traverses longitudinally along the part. An example of the type of part that is being design is a small car body. One student is working on a replica of a guitar. Students can create their designs in Inventor, save them as .stl files, similar to the format for the 3D printer, and then import their files into special software on the machine. Two afternoon students have been driving the effort to get the lithophane and 4th axis milling features on the Denford Mill to work successfully. They have done an excellent job of working through the program documentation and doing critical analysis of successes and failures with several prototypes until they came up with the final settings.
Next week, another shortened week, students will continue to work on all of these projects. We will also spend several days learning how to weld mild steel and aluminum using the TIG and MIG welders. We will also be working with the Torchmate cnc plasma torch.
For the majority of this week, students have been working on the Tic Tac Toe project creating a game board using multiple tool paths on the Techno mill and creating game pieces using the laser engraver and/or the 3D printer. Students have selected a wide variety of themes and designs for their projects and are working together to resolve design and machine tool path generation issues. Two students have also been working on more advanced features of the Denford milling machine including milling out images on lithophane plates that at first glance appear to be machined parts, but when held up to the light appear as photographs. Their second project has been to bring online the 4th axis milling feature using the trunion mounted rotating fixture. This allows the milling of three dimensional objects on all sides from a round or square billet of stock. The balance of the students will create designs of their own choosing based on the ground work laid by these students.
As we are in the midst of the build season for the district FIRST Robotics team, several students who are members of the team are supporting the work by machining parts for the robot frame. This work has involved Inventor design work, Mastercam and then first milling prototype parts out of wood and Masonite and then final parts out of aluminum. This work should continue well into next week.
Students are also working on another Inventor project to design and 3D print two chess pieces. One of the pieces needs to be a knight for complexity while the other piece is to be somewhat symmetrical to potential mill on the Denford mill.
Part of the shortened Thursday class was spent going through Professionalism topics, including reviewing resume’s and discussing skill sets needed for internships.
Next week students will finish the Tic Tac Toe project and will also go through several units covering design for manufacturability techniques, bad designs and how to avoid them and also calculations for speed and feed rates.
This week students have concentrated on all of the nuances involved with part design, cnc tool path generation, how to securely mount work product to the mill table and actual machining of parts. The base assignment has been to create a design in Inventor to be milled out of an approximately 5 inch square piece of wood, create a cnc tool path for the design using Mastercam and then mill the parts out on the Techno mill. We are calling this initial project the “Coaster Project” because most of the parts end up looking like elaborate coasters. Students have created a wide variety of shapes and designs for the parts. Some of the parts have intricate tool paths requiring bits as small as 1/32” in diameter. Even at that size, the mill cannot create the fine lines that some of the designs call for, so students have been using the laser engraver for finishing operations such as text. Along the way we have learned about depth cuts and the critical importance of knowing the material thickness, tool length and amount of cut through. Some students have run their parts multiple times to get them just right, but all of the designs are turning out well.
Our next project continues with the same criteria of an original design in Inventor that will be milled on either the Techno or Intelitek mills. The assignment is to create a Tic Tac Toe board using game pieces and a board design at the student’s discretion. The game board is to be machined on a mill while the game pieces can be laser cut, 3D printed or also cut on the mill. An example of a design is one that uses KU Jayhawks and K-State Wildcats for the game pieces. The game board itself could be cut in the shape of a football or basketball and have laser engraving on the face. A student in the fall created a three dimensional game board. The importance of this assignment is the introduction of tolerances. The game pieces will have to fit into depressions in the game board, but be loose enough to easily be removed. If too loose or close a tolerance is selected, then the parts will not fit properly. This project should complete about the middle of next week.
Next week we will spend more time learning about the calculations required for determining milling speeds and feed rates for different types of end mills and for different types of materials.
To begin the week students worked on their first project using Mastercam to define cnc tool paths rather than writing code from scratch. Everyone drew the identical image in Inventor and then imported the image into Mastercam. Right away we learned the importance of using the appropriate plane in Inventor to have the part orientated correctly in Mastercam to work with the cnc mills. We worked through all of the parameters for setting up Mastercam to work with the Intelitek mill for this part. We decided to use three different tools for this part. This required careful set up of the mill to make sure the correct first tool was selected according to each student’s program for the part to cur correctly. Along the way as we found some pitfalls, students learned how to change tool bits and to set their offset length in the tool library. Eventually we were able to work out all of the bugs that had resulted in either cutting in the air, or milling too deep into the part. We have been working with Mastercam on some post processor issues for the Intelitek Mill. This was the first time we have been able to successfully use the most recent post file from Mastercam for a multiple tool operation.
Students are now working on their initial design and mill project. The project is to design something relatively complex in Inventor, import it into Mastercam and then mill it out on the Techno mill. The features of the techno mill, including an automatic tool changer, are different from the Intelitek mill, so students will be using a different post processor. In the initial progress on this project we are learning that even though a design looks terrific in Inventor, when it gets to the actual tool path in Mastercam, there are the real geometric constraints of tool diameter and cutting length that need to be considered. In short, some students are switching to a post operation lazed engraving for lettering that is too small for the mill. Students will be machining these projects into the early part of next week.
Next week, we will spend time finalizing the set up and safe operation training for using the Techno mill and also will work on another Inventor design project using the 3D printer.
During this week students have concentrated on learning a new foreign language called G&M codes. This is the machine tool language that is the basis for cnc machining. As an introduction to this language students have been working on writing a program to mill their initials into a sample block. The assignment is to create two programs, on in absolute and one in relative coordinates. The path of the milling is to be identical so the accuracy test is to see if the mill follows the same path when either program is run. Using absolute coordinates, all coordinates are measured in terms of a defined origin point. In relative (or incremental) coordinates, each coordinate is measured from the last position, so essentially when the mill goes to a position, the coordinates of that position are reset to zero and the next position is measured from that new zero position. It is similar to providing driving directions to someone trying to get to your home. Each segment is described in terms of where you are at.
After successfully milling the initials in the sample blocks, students are now starting to learn how to use Mastercam to create the machine tool paths. Students start with drawing a part in Inventor and then use Mastercam to identify surfaces (faces and edges). Once the geometry is defined for a toolpath there is a selection process to define the end mill, spindle speed, feed rate and depth cuts for each toolpath. After all of the tool paths are defined, the file is “posted” which really is a translation process to make the generic code specific to a particular mill. Students then load the post file into one of the three mills and verify on an animation screen (make corrections as needed) and finally run their parts. With students learning the actual code in the first assignment, they are better equipped to troubleshoot faults in the Mastercam code as needed.
Once the initial Mastercam milling project is complete early next week, students will begin working on their own designs for parts to mill on one of the three milling machines in the classroom.
After beginning the week with an all CAPS orientation meeting, we continued to have orientation activities in the CIM class that included some "getting to know you" exercises, exploration of the shop to locate materials, tools and machines and equipment demonstrations. In addition to providing a means for students to get to know each other to foster team relationships, the second goal of the activities is for students to learn the location and correct (safe) use of all the resources of the CIM classrooms so that they can be independent when they are creating their own projects.
One of our introductory assignments was to review some facts and figures based on social, economic and technology status in the United States in the year 1910. After reviewing this data students responded to questions that asked them to predict what life will be like 100 years from now in terms of energy sources, transportation, space exploration, environmental factors, political and standard of living issues, robotics and what the classroom of the future would look like. Students were also asked to identify three inventions that have not yet been created but will be in place 100 years from now.
Solid modeling is the foundation of the prototype creation portion of the CIM class. 3D printing, laser engraving and cnc machining all start with some sort of 2D or 3D model. We switched the curriculum around to have students work on a design project to hone their skills using Autodesk Inventor© software. Students needed to respond to questions involving the cost, mass, volume and surface area of the parts they drew as a part of this assignment.
Towards the end of the week, the classes spent time doing hands on safety and operation training for some of the fixed machines and the hand tools for the class. The remaining machines will be introduced on an as needed basis as the semester progresses.
This week students will begin their first cnc machining project by writing g and m code from scratch and then using Mastercam to apply machine tool paths.