Continuous-Bed 3D Printer
The Advanced Structures and Composites Center (ASCC) is interested in the ability to 3D print parts beyond the print area of a given 3D printer. The ASCC uses additive manufacturing (AM) to print models of the products, prototypes and components that they produce. One innovation they have implemented is a printer that can print at an angle, eliminating the need for support material. Currently, the part size is dictated by the print volume of the printer. The task is to design and implement a method of allowing a machine to effectively print infinitely in one direction. There are a few patented commercially available continuous 3D printers that utilize conveyor belts, thus eliminating the possibility of using a belt to feed the part out of the print area. This continuous desktop printer should be designed to be scaled to a larger printer to be used later by the ASCC to print boat molds. Given the high weight of the boat molds it has been requested that the gantry handle the X, Y, and Z movements.
3D Printing Background
Introduction into 3D Printing
3D printing, a type of additive manufacturing, is the process of making three dimensional solid objects from a digital file.
The creation of a 3D printed object is achieved using additive processes. In additive manufacturing processes, an object is created by laying down successive layers of material until the object is created. These layers can be seen as a thin horizontal ridges on the cross-section of the object.
3D printing allows for the production of complex geometry and internal structures that would be impossible on other conventional manufacturing processes.
The Limitation of Print Volume
The maximum size of any part that can be printed on a 3D printer is governed by how far the print head can move. This is usually described as the print volume. Increasing this print volume results in bigger, more expensive machines. This project aims to modify a commercial 3D printer to print with an angled print head and extend the y-axis infinitely.
The angled printing code has been debugged and is functioning properly, however part to bed adhesion continues to be an issue. Best practices are being developed to attain the best adhesion, with external work-holding being considered. machining is also continuing on the bed and shaft mounts, with modification to the frame set to begin once the bed adhesion is solved. Also, the electromagnetic brake and required supporting hardware is being further developed.
The code for angled printing has been transformed and debugged, and printing at the angle has been successful thus far, however bed adhesion is proving to be an issue. Due to the geometry of the now tilted nozzle, the freshly extruded material is not as firmly pressed into the print bed as when it was parallel to the build surface. This leads to poor adhesion of the filament and the surface. Ways to combat this without heating the bed are being explored. Once the adhesion issue is resolved and verified, the machine will be torn down for the final modifications.
Weekly Update 2/19
The extruder heating issue has been resolved. After troubleshooting and consulting with others knowledgeable in FFF printing, the thermistor was determined to be faulty from the manufacturer. A new working thermistor has been acquired, and is being swapped. The tilted head has also been prototyped. The angle of the bend on the head is critical, with angular tolerances currently being determined.
Weekly Update 2/13
A free workspace was generously offered to us in the Advanced Manufacturing Center (AMC), which will provide the team with a consistent environment to print in and after hour access. Up until now, the printer and all work has been done in the MTL's unheated capstone work area or classrooms, which has limited the amount of progress due time conflicts and the environmental requirements for FFF printing. The printer has not had a successful print yet. Issues persist with the thermistor that provides temperature feedback from the extruder head. Without accurate feedback, the controller cannot determine the current extruder temperature and will continually heat it, posing a fire hazard. The current focus for the team is to determine the root cause of the heating issue.
Weekly Update 2/3
The Printer has been fully assembled, with test prints set to begin on 2/4. The next two weeks are set aside to troubleshoot the unmodified printer, and to take measurements and begin a detailed drawing packet for the indexing bed modifications. After these drawings are completed, manufacturing of the shop-made parts will begin, and orders will be placed for the purchased parts. After the unmodified machine is printing at a satisfactory level, the extruder will be tilted, and troubleshooting of the tilted printing will begin.
Weekly Update 1/24
Over break, the printer arrived at the ASCC and has been delivered to the MET workshop. After inspecting the contents of the package, assembly was started. Sticking to the schedule, we aim to have a fully assembled and functioning printer by February 1st. Only after the printer is functioning in its original configuration will modifications begin. This will reduce the possible sources of problems while troubleshooting. As the semester is beginning, revisions are being made to IR2 and the chosen solution is being further refined.
Weekly Update 12/7
Concern was raised about the adhesion of the filament on the printed part after it has had time to cool during indexing. Test specimens were designed and printed for tensile tests. While dimensions were kept consistent, half of the samples where allowed to fully cool half way through the print, then resumed to complete the print. Analysis is being performed on these tests to determine the severity of the adhesion issue. Solution concepts for indexing the bed are being evaluated and eliminated, striving for a cheap, effective solution. Solidworks design has begun on the printer, allowing modifications to be made in CAD to determine their feasibility and other constraints.
The East 3D Gecko has been ordered by the ASCC, and is expected to arrive within the next week. Having chosen a printer, the dimensional details and design can begin to be considered in conjunction with each of the preliminary solution concepts. Air bearings, PLC control, multi-stage vacuum ejectors, stepper/servo motors, precision linear motion and the industry work surface indexing are currently being researched. All of the concepts will be developed further and compared against each other. After the most suitable solution is determined, detailed design of the prototype will begin. Work on interm report two had begun and will progress for the next two weeks.
Weekly Update 11/19
After much research and deliberation, the team has settled on the East 3d Gecko as the printer that will be modified. The Gecko offers numerous benefits over other commercial printers. Firstly, the print heads travels in the X, Y and Z axis which leaves the bed stationary. Also, it's extruded aluminum frame will be easier to modify than a cast plastic or metal frame. However because the Gecko is a kit build, the team will have to dedicate time to assemble and troubleshoot before any modification can be done. The development of methods to incriminating the print surface will continue. As methods are evaluated, those outside the scope of the project will not be considered further.
Weekly Update 11/13
Research continues on methods of indexing the table, stepper motors, materials and printers. Three candidate printers have been identified and will be compared against each other to determine the most suitable model for modification. These printers are the Titan XY kit, the East 3D Gecko, and the M3D Micro +. The second client meeting will take place on 11/14, where project deliverable and design criteria will be solidified.
About the Team
Ian is a 4th year Mechanical Engineering Technology student from Fairport, NY. He is currently employed at the Advanced Structures and Composites Center as a student research assistant operating, maintaining, and modifying different 3D printer models. Upon graduation, Ian would like to work in the additive manufacturing industry.
Chris is a 4th year Mechanical Engineering Technology student from North Yarmouth, ME. He is currently employed the Advanced Structures and Composites Center working on the fabrication of a composites bridge girder using 3D printed molds. Chris would like to work in aerospace industry upon graduation and has spent two summers as an Aeromechanics intern at NASA Ames Research Center.
Noah is a 4th year Mechanical Engineering Technology student, originally from Walpole, MA. He is currently employed at Somic America, inc. as a Manufacturing/Quality Engineering intern. After Graduation, Noah wishes to advance and adapt his engineering skillset in the manufacturing industry.
(585) 260 – 9631
(207) 650 – 3374
(617) 529 – 5660
Keith Berube, Ph.D., P.E.
Assistant Professor, Mechanical Engineering Technology
207.581.2342 / 5711 Boardman Hall, room 204
Rachel Knapp – Preliminary Patent Search Assistance
Aaron Grant – 3D Printing Tensile Test Help