Aspect Biosystems RX-1 Chuck Cover

thingiverse

A cover for the vacuum chuck on the Aspect Biosystems RX-1 Bioprinter (1). This cover is designed to sit over the chuck, becoming the surface on which you place the mesh print surface. It has an array of 36 × 36 square holes as a pathway for vacuum and buffer, a cutaway for the vacuum tubing, and ‘handles’ to pick up and move the bioprinted tissue and mesh without needing to disconnect the chuck. This makes it much easier to move the printed tissues to a larger work area, rather than having to work on the printer. The handles also have flat surfaces for clamping the mesh between a second holder/shim planned for future designs, using a 19 mm bulldog clip. In the last photo, the chuck cover is shown on the printer, fitted with a membrane, and sitting above our waste tray design (2). The two designs work very well together! Credit to Michelle Guimond for her invaluable assistance with the design process. 1. <a href="https://www.aspectbiosystems.com/technology#bioprinter">Aspect Biosystems RX-1 Bioprinter</a> 2. <a href="https://www.thingiverse.com/thing:4213526">Aspect Biosystems RX-1 Waste Tray</a> *If you use this design in a scientific manuscript, I only ask that you please state the design was received from Dr. Adrian West, cite this webpage, and send me a link to your published paper!* <b>NOTE: I am putting print instructions here, because Thingiverse does not properly parse paragraphs in the print settings section below.</b> The number of fine features on the initial layer, and the need for a perfectly flat surface on which the mesh is placed, make this a tricky print. Printing on high quality glass with proper temperature and adhesive is essential. For BASF PET we use 65°C, Ultimaker glass, and Magigoo Original. For Ultimaker PC we use 110­°C, Ultimaker glass, and Dimafix Pen adhesive applied in a smooth uniform layer. Finally, your bed levelling and Z-offset must be perfect to ensure the proper balance between 'smooshing' to the glass surface without causing expansion that would fill in the holes; the automatic bed levelling of the Ultimaker S3 makes this easy, although sometimes 10-20 µm of Z-offset is required. Line widths and other slicer settings must be set very carefully. The 0.5 mm lines that create the outside of the holes were designed to print with two-passes of an Ultimaker 0.25 mm AA Print Core and 0.25 mm line width, but could probably also be printed with two 0.25 mm line widths from a 0.2 mm nozzle, or a single 0.5 mm line width from a 0.4 mm nozzle. The initial layer line width must be set at 100%, and a 0.2 mm initial layer height works well with the 0.25 mm AA Print Core. Any horizontal expansion setting other than zero will destroy the hole array. Try and avoid any setting that results in the slicer filling small gaps between the lines, and ensure that there are no retractions occurring within the hole array. Both outcomes would dramatically increase print time and potentially cause over-extrusion or oozing that might seal the holes. Printing slowly is recommended for accuracy, water tightness and layer fusion; we use 15 mm/s for the initial layer, 20 mm/s for outside walls, and 30 mm/s for inside walls for both PET and PC. The cover is designed with several different internal dimensions of 60.6 through 60.9 mm, which can be used to produce a print with measured internal dimensions of 60.1-60.2 mm depending on your material and printer (PET works well at 60.6, PC at 60.8 to 60.9 mm). This allows you to create an ideal balance between loose fit for easy removal, but still prevents lateral movement during printing. If your print is too large or too small, flow settings could also be modified to achieve a perfect fit, but I must stress again that you should not set horizontal expansion at any value other than zero. PET is the easiest material with which to print this, because it allows sanitisation with 70% EtOH and long term water exposure without fear of degradation. Printing in PC allows you to boil the part as an additional sanitisation step, but the part often warps slightly, causing the base to not be perfectly flat. UV, gamma or ethylene oxide are also good sanitising possibilities. However, for the purposes of biosafety, I would consider the part non-sterile before use and biohazardous after use. Disposal should be by autoclaving with other solid waste.