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1. Embed this notice
   Koz Ross (koz@chaos.social)'s status on Tuesday, 01-Apr-2025 10:04:53 JST Koz Ross

   • 3D Printing

   Qidi 'engineering' strikes again: https://www.reddit.com/r/3Dprinting/comments/1jnuju1/rqiditech3d_permanently_banned_me_for_warning/

   tl;dr - a Qidi Plus4's SSR (which we have been warning about since day freaking 1) finally blew and caught fire, with serious consequences.

   I've said it before and I'll say it again: do not buy Qidi printers, don't suggest others buy Qidi printers. This isn't just sloppy engineering, this is outright dangerous.

   #3DPrinting #FDM

   @3dprinting

   • Embed this notice
     Rich Felker (dalias@hachyderm.io)'s status on Tuesday, 01-Apr-2025 11:23:21 JST Rich Felker

     in reply to

     • 3D Printing

     @koz @3dprinting I want to implement an analog safety for this case (heater mosfet/ssr fails closed):

     Crowbar circuit that's essentially an xor gate on heater mosfet gate and output. If they don't match, it closes another chonky power mosfet shorting the psu and blows the fuse.

   • Embed this notice
     Rich Felker (dalias@hachyderm.io)'s status on Tuesday, 01-Apr-2025 11:24:37 JST Rich Felker

     in reply to

     • 3D Printing

     @koz @3dprinting (For mains heater, this would blow the circuit breaker at the panel, but would need secondary mains rated ssr for the crowbar.)

   • Embed this notice
     Rich Felker (dalias@hachyderm.io)'s status on Tuesday, 01-Apr-2025 11:33:31 JST Rich Felker

     in reply to

     • 3D Printing

     @koz @3dprinting Crowbar circuits in general are an awesome underappreciated family of safeties I love.

     Instead of trying to shut off current, which won't always be possible, provide a sudden alternate zero resistance path for the current to take and let nature take its course.

   • Embed this notice
     Rich Felker (dalias@hachyderm.io)'s status on Tuesday, 01-Apr-2025 11:59:16 JST Rich Felker

     in reply to

     • 3D Printing
     • Kyle Davis
     • LisPi

     @linux_mclinuxface @lispi314 @koz @3dprinting Using cheap or even poor quality cheap parts is not necessarily bad engineering if you can ensure that it still fails safely.

   • Embed this notice
     Kyle Davis (linux_mclinuxface@fosstodon.org)'s status on Tuesday, 01-Apr-2025 11:59:17 JST Kyle Davis

     in reply to

     • 3D Printing
     • LisPi

     @lispi314 @koz @3dprinting let me be clear, I’m not defending qidi, but I don’t agree that cheap parts are equal to bad engineering.

   • Embed this notice
     LisPi (lispi314@udongein.xyz)'s status on Tuesday, 01-Apr-2025 11:59:18 JST LisPi

     in reply to

     • 3D Printing
     • Kyle Davis
     @linux_mclinuxface @3dprinting @koz Aren't those synonymous?
     
     Using cheap parts /is/ bad engineering.
   • Embed this notice
     Kyle Davis (linux_mclinuxface@fosstodon.org)'s status on Tuesday, 01-Apr-2025 11:59:19 JST Kyle Davis

     in reply to

     • 3D Printing

     @koz @3dprinting Jesus, those are scary pictures.

     It’s interesting that the OP calls out cheap parts instead of bad engineering. Probably a little of this, little of that.