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



10
3
30


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)


8
2
16


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


10
1
10


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


10
1
10


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


3
3
9


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


8
1
8


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


3
2
6


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)


3
2
6


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


3
2
6


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



2
2
4


kink protection for filament (filament guide → PTFE)
check for blockages in the hotend