# Risk analysis for Hangprinter with FDM extruder
**risk****possible damage (1-10)** **1 = minimum, 10 = maximum****probability of occurrence (category)** **1 = low** **2 = medium** **3 = high** **rating= scope of damage x probability of occurrence****counteraction(s) and hints**
**line construction** - lines break / loosen - guests / guides get tangled → risk of injury (stumbling, pinching off; possibly burning at the hot end - construction is badly damaged 10330- suitable shut-off of the device operation / entering the construction only by trained personnel - check deflection pulleys, check parts for sharp edges or generally mechanical contact points for abrasion - check lines knots → do not use simple knots; use special knots - use of tear-resistant lines (special fishing line with sufficient traction and diameter) - occasional inspection / maintenance (protocol)
**parts of the machine fall off** - e.g. screws or plastic parts - visitors could get hurt - machine could be damaged (malfunction) 8216- secure screws with screw locks or use stop nuts - check the connection stability in an acceptance report - occasional inspection / maintenance (protocol) - produce parts from elastic material (tendency to brittle fracture / prevent cracks) → use a high degree of infill
**hotend or extruder smokes or burns** - device destruction - smoke detectors and sprinkler systems damage the exhibition - filament / substrate is set on fire 10110- redundant thermal sensor - recent firmware with temperature jump measurement, watchdog and automatic emergency shutdown - safe installation of the sensors (gluing / screwing) - regular inspection / maintenance (protocol) - **consequences when entering are destructive**
**controller parts smokes or burns** - device destruction - smoke detectors and sprinkler systems damage the exhibition 10110- electrical inspection / acceptance with detailed protocol - buy high quality electronics - use high quality wiring / cabling and shielding (generous cross-sections, good manufacturers) - **consequences when entering are destructive**
**Software** - print does not start - print result does not match the input 339- extensive testing and logging / documentation - establish remote maintenance routines
**collisions between printed part and lines** - design-related variability of the possible pressure dimensions depending on height Z - The machine could tangle and damage itself 818- simulation of the model to be printed with the appropriate software
**errors in print part - vibrations during printing** - by heavy trucks driving next to the building - by wobbling on the frame by guests / visitors 326- store the machine on a tight (spring) frame - situate warning panels with information like "Do not touch.", Print may loose traction." or similar - select the line diameter so that the installation becomes stable against stretching
**material loss - tool oozes** - material spills uncontrollably on the printing platform or at other points in the effective radius of the machine - due to insufficient screwing between the hot end heating block and the nozzle (thermal transition zone) 326- check for tightness of the strand components and note them in the acceptance report - regular inspection / maintenance (protocol) - no further countermeasures possible (cannot be checked - only optically)
**material does not stick → " spaghetti salad"** - at the start of printing - during printing - leads to wasted material 326- regular cleaning of the printing surface - check the distance between the platform and nozzle - check the overhang angle in the print model and calculated support structures - checking the printing parameters (layer height, extruded volume per unit of time, etc.) - establish stability in the printing frame (no accidental offsets by warping the machine frame → thus offset in the printing part)
**material extrusion fails**- extruder problem (clogging) / mechanical defect / heating failure - material feeder blocked - material torn 224- kink protection for filament (filament guide → PTFE) - check for blockages in the hotend