# Toolhead fell mid-print! **URL:** \ **Category:** U1 Troubleshooting guides\ **Created:** [December 7, 2025, 3:10am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614 "2025-12-07T03:10:55Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![ni42](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/ni42/32/33566_2.png) [@ni42](https://forum.snapmaker.com/u/ni42)\ **Post date:** [December 7, 2025, 3:10am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/1 "2025-12-07T03:10:55Z")
Hi Snapmaker Dev team, I’d like to share a recent case and suggest a potential firmware safeguard to help prevent a similar issue in the future. During a multi-tool print, I used **PETG as the support interface** , but the interface detached mid-print and led to a toolhead failure. ![IMG_2398](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/3X/b/8/b89472caa26d945bf7c215c2fa3cc3894e0e5016.jpeg) ![IMG_2399](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/3X/0/d/0d7035d5fe1543ee378e42da25658aef3c970669.jpeg) ![image](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/3X/5/7/5750d5e98ae34bef56bcc628839f99d22f1ba3ec.jpeg) ### Toolhead Setup: - **Toolhead 2:** White PLA - **Toolhead 3:** Green PETG - **Toolhead 4:** Black PLA ### Hypothesis of What Happened: 1. Toolhead 2 printed the PETG interface layer, but it **did not adhere properly to the PLA support base**. 2. The detached PETG interface was carried back to the **Toolhead 2 parking position** , there was **residual PETG blob on the toolhead base**. 3. The carriage then picked up **Toolhead 4** and continued printing black material over the white support, **despite the missing interface layer**. 4. Later, the carriage parked **Toolhead 1** and attempted to pick up **Toolhead 2**. 5. At this point, **Toolhead 2 did not lock properly and fell off mid-print** , causing: ### Suggestion It may be beneficial to add a **firmware-level safety check** to: - Detect abnormal toolhead locking conditions - Pause the print if a toolhead pickup or locking is not completely secure. Thanks _PS: This must be the first case reported for this, do i get an award. or icon? 😛_ Finally we have our own: ![PrusaXLDall](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/3X/9/6/96d21f40403d5feea5141fa80626c2f17539e16f.gif) ---
**Author:** ![ni42](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/ni42/32/33566_2.png) [@ni42](https://forum.snapmaker.com/u/ni42)\ **Post date:** [December 7, 2025, 3:28am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/2 "2025-12-07T03:28:23Z")
Here are some more tidbits from the console. ```auto // pressure_advance: 0.024460 // pressure_advance_smooth_time: 0.040000 14:58:06 // extruder1 -> extruder2 14:58:06 // Retrying to get normal extruder activation status (attempt 0), forced_park: False, retry_extruder_id: None 14:58:07 // Retrying to get normal extruder activation status (attempt 1), forced_park: False, retry_extruder_id: None 14:58:07 // Retrying to get normal extruder activation status (attempt 2), forced_park: False, retry_extruder_id: None 14:58:08 // Retrying to get normal extruder activation status (attempt 3), forced_park: False, retry_extruder_id: None 14:58:08 // Retrying to get normal extruder activation status (attempt 4), forced_park: False, retry_extruder_id: None 14:58:09 // Retrying to get normal extruder activation status (attempt 5), forced_park: False, retry_extruder_id: None 14:58:09 // Retrying to get normal extruder activation status (attempt 6), forced_park: False, retry_extruder_id: None 14:58:10 // Retrying to get normal extruder activation status (attempt 7), forced_park: False, retry_extruder_id: None 14:58:10 // Retrying to get normal extruder activation status (attempt 8), forced_park: False, retry_extruder_id: None 14:58:11 !! Extruder extruder2 is not allowed to switch, detected that extruder1 is detached. err-sta: ['1-(FFF)'] 14:58:11 // Pausing.. ``` ---
**Author:** ![nweolu](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/nweolu/32/23079_2.png) [@nweolu](https://forum.snapmaker.com/u/nweolu)\ **Post date:** [December 7, 2025, 7:29am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/3 "2025-12-07T07:29:40Z")
@Simon_Zhi for CV spreadsheet:) ---
**Author:** ![Wombley](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/wombley/32/27838_2.png) [@Wombley](https://forum.snapmaker.com/u/Wombley)\ **Post date:** [December 7, 2025, 7:33am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/4 "2025-12-07T07:33:50Z")
Do you mean @Simon_Zhi ? 👀 ---
**Author:** ![Cylonmode](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cylonmode/32/30291_2.png) [@Cylonmode](https://forum.snapmaker.com/u/Cylonmode)\ **Post date:** [December 7, 2025, 1:46pm UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/5 "2025-12-07T13:46:29Z")
I am beyond the point of frustration with my toolhead alignment issues. ---
**Author:** ![Simon\_Zhi](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/simon_zhi/32/30470_2.png) [@Simon\_Zhi](https://forum.snapmaker.com/u/Simon_Zhi)\ **Post date:** [December 8, 2025, 6:53am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/6 "2025-12-08T06:53:11Z")
Toolhead Coordinate Calibration Method： [Failure to launch - Calibration/toolhead parking errors - U1 Toolchanger / U1 Troubleshooting guides - Snapmaker: where creation happens](https://forum.snapmaker.com/t/failure-to-launch-calibration-toolhead-parking-errors/40574/13) You can refer to the calibration methods compiled in the official WIKI or forum posts to calibrate your toolhead pick-and-place coordinates. ---
**Author:** ![ni42](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/ni42/32/33566_2.png) [@ni42](https://forum.snapmaker.com/u/ni42)\ **Post date:** [December 8, 2025, 8:35am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/7 "2025-12-08T08:35:01Z")
@Simon_Zhi I don’t know if you read the post, because it’s not a calibration issue. Toolhead fell mid print because of obstruction is toolhead pickup and drop off location, ask is to add in firmware someway for system to error out if the lock in not successful ---
**Author:** ![Simon\_Zhi](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/simon_zhi/32/30470_2.png) [@Simon\_Zhi](https://forum.snapmaker.com/u/Simon_Zhi)\ **Post date:** [December 8, 2025, 9:01am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/8 "2025-12-08T09:01:23Z")
Sorry, I didn’t look closely the first time and thought it was a toolhead pick-and-place failure. Let me see if I understand you correctly: 1. You’re reporting that this incident caused the toolhead to fall off. 2. You’d like an added feature: if the toolhead detaches during printing, the job should pause immediately so it can be resumed later. ---
**Author:** ![ni42](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/ni42/32/33566_2.png) [@ni42](https://forum.snapmaker.com/u/ni42)\ **Post date:** [December 8, 2025, 9:40am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/9 "2025-12-08T09:40:44Z")
Yes, it fell mid-print. However, I’m asking if there’s a way to prevent the carriage from attempting to print if the lock is not secure. Falling toolheads can’t be good for anything. ---
**Author:** ![Simon\_Zhi](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/simon_zhi/32/30470_2.png) [@Simon\_Zhi](https://forum.snapmaker.com/u/Simon_Zhi)\ **Post date:** [December 8, 2025, 10:34am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/10 "2025-12-08T10:34:08Z")
We haven’t encountered this issue yet, so I probably can’t offer any effective advice. Generally, if there’s no physical resistance during the toolhead pick-and-place process, the toolhead can be properly locked onto the tool changer by the mechanical structure. But I checked with the tech team—switching toolheads does include a detach check, but there’s currently no mid-print detection. They’ve added the request to the backlog and will optimize it later. **Thank you very much for your feedback！！！** ---
**Author:** ![ni42](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/ni42/32/33566_2.png) [@ni42](https://forum.snapmaker.com/u/ni42)\ **Post date:** [December 8, 2025, 4:10pm UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/11 "2025-12-08T16:10:53Z")
Certainly, I haven’t encountered anyone else reporting this issue so far. That’s why I tried to provide lots of details. What I am thinking carriage should have paused as soon as it was not able to form the secure lock with toolhead not when it tried to print. I’m happy to provide any additional information your tech team may require. ---
**Author:** ![Simon\_Zhi](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/simon_zhi/32/30470_2.png) [@Simon\_Zhi](https://forum.snapmaker.com/u/Simon_Zhi)\ **Post date:** [December 9, 2025, 3:01am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/12 "2025-12-09T03:01:35Z")
If you encounter this situation again, I hope you can immediately provide us with the saved logs. Based on this type of situation, we will launch a machine-side log upload function before the end of the year. ---
**Author:** ![Boxkite](https://avatars.discourse-cdn.com/v4/letter/b/df705f/32.png) [@Boxkite](https://forum.snapmaker.com/u/Boxkite)\ **Post date:** [December 9, 2025, 8:19am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/13 "2025-12-09T08:19:49Z")
> [@ni42](#): > > What I am thinking carriage should have paused as soon as it was not able to form the secure lock with toolhead not when it tried to print. This is the problem with not having any electrical connection at that point. ---
**Author:** ![Wombley](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/wombley/32/27838_2.png) [@Wombley](https://forum.snapmaker.com/u/Wombley)\ **Post date:** [December 9, 2025, 9:19pm UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/14 "2025-12-09T21:19:07Z")
I’m genuinely surprised. I think you mentioned on Discord, you did not see the failure in action. Are you certain that the printhead detached while printing? As far as I know, if the head is successfully picked, there’s almost no way for it to detach once pulled from the docking pin. Although it is possible for it to get knocked from the docking position then stop. I guess Snapmaker can say exactly how “successfully picked” is detected. But I mean, it would not resume printing _unless_ the head were securely attached, afaik. And in that case, I’m not sure how it’s possible for it to come off until a park is later attempted. ---
**Author:** ![ni42](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/ni42/32/33566_2.png) [@ni42](https://forum.snapmaker.com/u/ni42)\ **Post date:** [December 10, 2025, 2:21am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/16 "2025-12-10T02:21:49Z")
Yes, I wasn’t home when that happened. The toolhead is in the middle of the plate, and I’m sure the carriage brought it there. I guess it was able to pick up the toolhead, but since it wasn’t secure, it eventually fell. That also explains why the bottom cover of the carriage fell; it must have been because of the weight of the toolhead. Maybe carriage carried it on the toolhead cover.. ---
**Author:** ![Cylonmode](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cylonmode/32/30291_2.png) [@Cylonmode](https://forum.snapmaker.com/u/Cylonmode)\ **Post date:** [December 10, 2025, 12:22pm UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/17 "2025-12-10T12:22:24Z")
Sounds like an alignment issue with the toolhead just like I have been having… Those are all the same things happened to me. Sometimes the bottom cover of the carriage would get ripped off when changing toolheads. You “might” need to adjust your alignment coordinates. This problem has been plaguing my machine, although I haven’t had the bottom plastic cover of the carriage rip off in awhile. ---
**Author:** ![ni42](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/ni42/32/33566_2.png) [@ni42](https://forum.snapmaker.com/u/ni42)\ **Post date:** [December 10, 2025, 4:05pm UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/18 "2025-12-10T16:05:55Z")
It’s not alignment issue. If you see I mentioned that how their is petg support interface layer where tool head 2 parking spot is. Never had issue with alignment and worked fine once I put it back. ---
**Author:** ![Simon\_Zhi](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/simon_zhi/32/30470_2.png) [@Simon\_Zhi](https://forum.snapmaker.com/u/Simon_Zhi)\ **Post date:** [December 11, 2025, 2:13am UTC](https://forum.snapmaker.com/t/toolhead-fell-mid-print/40614/19 "2025-12-11T02:13:59Z")
My guess is that PETG and PLA don’t bond, causing the part to shift or slide and eventually become a physical obstruction.