3D PRINTER STUDENT GUIDELINES

Transcription

1 3D PRINTER STUDENT GUIDELINES Digital Fabrication Laboratory Hours 10am - 3pm (Monday-Friday) abp-fablab@unimelb.edu.au Contact A, First Floor, 757 Swanston st Faculty of Architecture Building & Planning, University of Melbourne 3D Printer Guidelines, August

2 Disclaimer: The FabLab cannot guarantee jobs will be completed by the date required especially when the FabLab is busy at the end of each semester. It is each students responsibility to submit their work with enough time for the FabLab to complete the job. If work is needed urgently you may need to make other fabrication arrangements. The Fab Lab provides equipment and facilities to help students build physical renders and models of their computer generated designs. The equipment in the Fab Lab enables students to produce extremely accurate models and reduce the time spent constructing these models. Please remember that for OH&S reasons students are not allowed beyond the reception desk in the FabLab. Students must read all Guidelines and instructional material before seeking help from FabLab Staff as staff do not have time to give lengthy instructions. FabLab staff may reject work if it is deemed an ineffective use of the equipment. Please do not harass FabLab Staff. Jobs will be completed as quickly as possible. No student will be allowed to skip the queue so make sure jobs are submitted with adequate time for completion and submission.

3 3D Printing Fact Sheet 1. Overview of Laser Cutter Operating Procedure File Preparation CONTENTS Overview of 3D Printer Operating Procedure 2. Cost of 3D Printing 3. Printable Area 4. Solid Water-tight Models 5. Minimum Wall Thickness for 3D Printing 6. Saving Money 7. Hollow Parts 8. File Submission Procedure File Preparation Scale, Printable Area, STL File Format 10. Step-By-Step Model Making File Submission Procedure 11. Step-By-Step Model Making 1. Design Your Project Create a Water-tight model Convert the model in Mesh Check for Errors in the Mesh Export File as STL Submit your file Check no errors in 3D Print Software 18.

4 3D PRINTING FACT SHEET QUICK NOTES This prage provides the basic information requried to utislise the 3D Pritner in the FabLab. MINIMUM WALL THICKNESS The minimum printable wall thickness is 2mm COST OF 3D PRINTING PRINT COST = Vol (cubic Inch) x $5 PRINTABLE AREA 200 X 200 X 200 mm SOLID WATER-TIGHT MODELS To be printable your 3d model must be composed of solids. Solids are closed polysurfaces or meshes meaning there are no holes or missing surfaces in them. If you were to imagine them as physical volumes they should be watertight or able to carry water without leaking. SAVING MONEY Hollow Parts - You only pay for the solid printed area. Therefore by removing the interior of your object you can reduce the printing price. Scale - The printing price is directly related to the printed volume, and volumes are the third power of the objects size. Make the object half the size and volume will become an eighth. STL FILE FORMAT Solid, watertight files must be submitted to print as STL mesh files. Export your model as an STL from your 3D modelling software.

5 OVERVIEW OF 3D PRINTER OPERATING PROCEDURE QUICK NOTES Introductory workshops will be carried out at the beginning of each semester. Please enquire within FABLAB for more details PAGE 1 OPERATING PROCEDURE 3D Printing is an additive manufacturing process of making three dimensional physical objects from digital models. These physical objects are created by adding or laying down and binding successive layers of material. The FabLab currently operates a Z Corp Z450 3D Printer. This printer produces three dimensional objects by binding or gluing successive layers of powder together in the area of the object. A thin layer of powder is laid across the print area. The print head then applies the binding agent in the areas where the object is solid. The print bed is then slightly lowered and the next layer of powder is scraped out and binding agent applied where the next layer is solid. All these layers combine to produce the physical 3D object. 1.1 CAD Software Mesh ZPrint Layers CAD software exports files in standard formats for 3D printing. The exported file is a mesh that encloses a 3D volume. 1.2 ZPrint software slices the 3D model file into hundreds of digital cross-sections, each corresponding to a layer of the model to be printed. 1.3 Each layer is printed one atop the other until the model is complete. ZPrinter Finished Model When the model has completed printing the loose support powder from each layer that has not been bound together is then removed using compressed air and vacuum units. The print is then left to dry and is then infiltrated or coated in a solidifying solution to give the print extra strength.

6 COST OF 3D PRINTING PRINTABLE AREA QUICK NOTES Cost = $5 per cubic Inch = $0.31 per cubic cm Print area = 200 x 200 x 200mm COST OF 3D PRINTING The cost of a 3D printed model is determined by the volume of the solid printed object. To estimate the cost to print your project calculate the volume of the print in cubic inches and multiply this by 5. PRINT COST = Vol (cubic Inch) x $5 PRINTABLE AREA The size of the print area in the Z450 printer is 200 x 200 x 200 mm. Any object to be printed must fit within this volume. If it is larger than this bounding area it must either be reduced in scale or broken into smaller sections that can then be reconnected after printing. 200 mm 200 mm 200 mm

7 MODEL SETUP: SOLID, WATER-TIGHT MODELS QUICK NOTES Your model must be composed of solids for it to be printable. To be printable your 3d model must be composed of solids. Solids are closed polysurfaces or meshes meaning there are no holes or missing surfaces in them. If you were to imagine them as physical volumes they should be watertight or able to carry water without leaking. A printable object can be composed of multiple solids that are intersecting. The printer software will read this as one closed volume. Intersecting Solids Or the solids can be Booleaned or joined together to produce one closed polysurface or mesh. If your 3d model is more complex it is advised to boolean the surfaces into one closed solid. Booleaned Solid

8 MODEL SETUP: MINIMUM WALL THICKNESS FOR 3D PRINTING QUICK NOTES Minimum Thickness = 2mm Minimum wall thickness is defined as the minimum thickness that your model should have at any one given point. In the image below, D3 is the minimum thickness. As a general rule, the minimum printable thickness is 2mm. D1 D3 D2 If you are designing a cylinder, the cylinder itself should at all times have a larger diameter than 2mm. If the cylinder is turned into a straw the edge of that straw should at all times be at least 2mm thick. > 2mm > 2mm

9 MODEL SETUP: MINIMUM WALL THICKNESS FOR 3D PRINTING QUICK NOTES Minimum Thickness = 2mm You may be able to achieve thinner elements than 2mm. The success of thinner elements than 2mm is determined by the geometry of the part and the load that will be placed on the element. The image below depicts a model where a lot of load is placed on a thin joint (A). This joint would be extremely weak and fragile. This would need to be made thicker in order to print. The thin strands and floor plates (B) would also be extremely delicate and susceptible to being destroyed during the cleaning process where compressed air is used to remove the support powder. If an element is too thin and delicate the compressed air will blow that part apart. LOAD B. B. A.

10 MODEL SETUP: SAVING MONEY QUICK NOTES Cost = $5 per cubic Inch The cost of a print can be reduced by: 1. Making the model hollow and 2. Reducing the scale of the model. 1. Make your model hollow. You only pay for the solid printed area. Therefore by removing the interior of your object you can reduce the printing price. (see Hollow Parts for more information). 2. Reduce the printed size, or scale, of the printed part. The printing price is directly related to the printed volume, and volumes are the third power of the objects size. Make the object half the size and volume will become an eighth. Scale 1.0 Scale cm 1.5 cm Vol = 8 cubic cm = $40 Vol = cubic cm = $16.87

11 MODEL SETUP: CREATING HOLLOW PARTS QUICK NOTES Cost = $5 per cubic Inch Print area = 200 x 200 x 200mm The price of a print is determined by the actual printed volume (not by the models bounding volume). An easy way to save money is by making your object hollow. There are some trade-offs to this: - Hollow objects will not be as strong as solid objects - Objects such as statues or tall top heavy objects may need a solid base to prevent the model from falling over. - It will increase the number of polygons in your model. - You will need to make sure that the walls of the hollow object remain thick enough. A cube in 3D modelling applications consists of six faces with empty space in between them. If this is to be 3D printed, this represents a solid volume. If you were to print this cube you would pay for all the solid printed material on the inside of the cube. The amount of solid printed volume could be reduced by hollowing out the cube. This can be achieved by offsetting the surface inwards in Rhino. The surface normals of the object need to face in the correct direction (indicated by the arrows below), outward of your objects. This is important because the surface normals determine which area is inside and outside of your object. Inside means printed material and outside means support material or unbound powder. You can check the surface normal direction in Rhino by using the Dir command. This will display arrows which represents the normal of the surface at each of it control points. If they are facing the wrong way use the Flip command to reverse their direction.

12 MODEL SETUP: CREATING HOLLOW PARTS As the support material is loose powder, the hollow cube will be full of this loose powder. You will therefore need to make holes in the cube to allow for the powder to be cleaned out of the cube. These holes should be at least 5mm wide. More holes should be added if the shape is more complex and would be more difficult to clean.

13 FILE PREPARATION QUICK NOTES SCALE The 3D models submitted must be scaled to the actual size they are to be printed at. The FABLAB will not alter the scale of the model as staff do not know what scale was intended. PRINTABLE AREA The correctly scaled model must fit within the printable area of 200 x 200 x 200 mm. If it is too large for this print area the model must be split into parts and printed as separate elements which are then joined together when printed. STL FILE FORMAT Solid, watertight files must be submitted to print as STL mesh files. Export your model as an STL from your 3D modelling software. If you are having trouble getting your file to a printable state please bring it to the FabLab in person in its original file format.

14 FILE SUBMISSION PROCEDURE QUICK NOTES Complete the job submission webform to be placed in the job queue. All 3d print files are to be submitted through the FabLab web page which can be found through the Faculty of Architecture Building & Planning home page or at If the STL file is larger than 10mb it will not be able to be submitted via the web-form and will need to be dropped off in person to the FABLAB. However you still need to complete the web form to place yourself in the queue leaving the attachment area blank. All fields marked required must be filled in by students selecting 3d Printer from the machine drop down menu. For each file submitted the job file attached must be correctly labelled in the following way: Student number_name_job number _JamesSmith_12 The job number refers to the number of jobs submitted by each student each semester to enable staff to easily identify the chronology of each students work. Therefore if James Smith was to submit 3 jobs over the semester the files would be labelled like this: _JamesSmith_ _JamesSmith_ _JamesSmith_3 Student s work will only be entered in the job queue once the form has been correctly completed and the attached file is deemed to be setup correctly in accordance with the relevant student guidelines for each machine. If there is a problem with the submitted file, FabLab staff will contact the student.

15 STEP-BY-STEP MODEL MAKING Step 1: Design Your Project Design your project using the chosen 3D modelling software that you have selected. This Step-by-step example will use Rhino as the 3D modelling software to check and prepare the project for printing. Important: The project must be created at the scale to be printed ensuring all wall thicknesses and geometry adhere to the requirements described in the above sections.

16 Step 2: Create a water-tight model Make sure the model is composed of intersecting solids or all solids have been booleaned together to create one close polysurface. The image below illustrates how intersecting solids can be used to create a printable volume. In this example the I beam extends into the surface of the floor.

17 Step 3: Convert the model into a Mesh 3D printers use STL mesh files. Therefore when you export your model as an STL it will convert it to a mesh if it is not already. To check the mesh is good to print you should always convert it to a mesh and check the model is in a printable state before exporting as a mesh. To convert a Nurbs model to a mesh in Rhino, use the Mesh tool. This allows you to determine the resolution, or amount of triangles used to create the geometry of your project. Remember the higher the resolution, the larger the file size.

18 Step 4: Check for Errors in the Mesh Rhino 5 enables you to run a basic mesh checking and repair procedure called Mesh Repair. This will enable you to check if the mesh is Good or ok to print. If there are inverted faces or holes in the mesh. It will also enable you to repair some of these errors through the automatic fixing tools. Important: Rhino only has a basic mesh repair tool. If you have made an extremely messy model with lots of holes, overlapping faces and intersecting triangles etc. it will not be able to fix all these errors. If you cannot get the mesh to a good mesh bring the file into the FabLab and staff will be able to direct you on the corrections that should be made. The FabLab has more advanced mesh repair software that can be used to correct errors if you are unable to do so using the standard mesh repair tools. It is expected however that you will make all efforts to rectify the problems yourself before contacting the FabLab. Important: It is each students responsibility to submit correct files and to rectify problems themselves. FabLab staff will attempt to provide assistance as needed however if the FabLab is busy this may not be able to be provided right away.

19 Step 5: Export file as STL To export the mesh as an STL use the export command and select STL from the file type drop down menu. When the STL Mesh Exporter Options window pops up (see image below), push OK. Save your STL with the appropriate file name as directed in the section above.

20 Step 6: Submit your file Submit your file for printing via the online submission form selecting 3d Printer and 3D scanner from the Machine drop-down menu and attaching your STL at the bottom of the page. Important: By completing the form you will place your project in the queue. If your STL file is greater than 10mb you will need to provide the file in person. Please make sure you still complete the submission form without the file attached as this will place you in the print queue.

21 Step 7: Check there are no errors in 3D Print software This step is complete by FabLab staff. Your file will be checked for errors with the 3D print software. If there are any errors identified you will be contacted and notified of the errors and how to correct them.

22 Step 8: Print project When your file has been approved and is in a printable state the FabLab staff will complete your print. Students need to allow 3 days to print, dry and infiltrate 3D prints to be ready for collection. The time will be longer if there are other jobs in the queue.