# U1 Top Cover questions **URL:** \ **Category:** U1 Toolchanger\ **Created:** [September 21, 2026, 12:21pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446 "2026-09-21T12:21:00Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Darik](https://avatars.discourse-cdn.com/v4/letter/d/3be4f8/32.png) [@Darik](https://forum.snapmaker.com/u/Darik)\ **Post date:** [September 21, 2026, 12:21pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/1 "2026-09-21T12:21:00Z")
Hi, I have a few questions about the Snapmaker U1 Top Cover that I couldn’t find answers to. 1. How to control the top cover and fan speeds when using OrcaSlicer? From what I found, fan speeds are set automatically when slicing in Snapmaker Orca, but how does this work with OrcaSlicer? 2. I have a question about Seal 1 for the printer’s glass door. All the other seals seem to fit against the frame, keeping particles in and sealing the gaps. But Seal 1 seems to just hide the gap. 3. Has anyone noticed a drop in PLA print quality with the top cover installed, or am I just being paranoid? 🙂 Thanks. ---
**Author:** ![CrazyIvan](https://avatars.discourse-cdn.com/v4/letter/c/7bcc69/32.png) [@CrazyIvan](https://forum.snapmaker.com/u/CrazyIvan)\ **Post date:** [September 21, 2026, 2:15pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/2 "2026-09-21T14:15:18Z")
> [@Darik](#): > > 1. Has anyone noticed a drop in PLA print quality with the top cover installed, or am I just being paranoid? I wouldn’t be surprised, PLA is known to print better in unenclosed printers. My advice would be to leave the door open and the cover panel in the top cover off. ---
**Author:** ![MAGNAC](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/magnac/32/24771_2.png) [@MAGNAC](https://forum.snapmaker.com/u/MAGNAC)\ **Post date:** [September 21, 2026, 2:25pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/3 "2026-09-21T14:25:59Z")
I’m testing without the top cover first, and then I’ll test with the front door open and the top hood open, to see if there’s any difference! ---
**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:** [September 21, 2026, 11:12pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/4 "2026-09-21T23:12:10Z")
I have not had issues with PLA in an 80 degree Fahrenheit room with the exhaust fan at 60%… But others have had issues with PLA, so everyone’s experience seems different. ---
**Author:** ![Zoe\_M](https://avatars.discourse-cdn.com/v4/letter/z/8491ac/32.png) [@Zoe\_M](https://forum.snapmaker.com/u/Zoe_M)\ **Post date:** [September 23, 2026, 11:13am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/5 "2026-09-23T11:13:30Z")
I’m afraid the original OrcaSlicer can’t manage the top cover. I saw a user mentioned once that when using G-code from OrcaSlicer, the top cover fan was always off. As for the front door seal, I’ll check with the engineer to see if I can find more details. Regarding PLA printing, I’ve also seen other users complain about the continuous temperature warning when printing PLA 😬 . When I first forwarded this feedback, I was informed that the fan control logic is still under optimization. ---
**Author:** ![Darik](https://avatars.discourse-cdn.com/v4/letter/d/3be4f8/32.png) [@Darik](https://forum.snapmaker.com/u/Darik)\ **Post date:** [September 26, 2026, 6:18pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/6 "2026-09-26T18:18:01Z")
> [@Zoe\_M](#): > > I’m afraid the original OrcaSlicer can’t manage the top cover. I saw a user mentioned once that when using G-code from OrcaSlicer, the top cover fan was always off. Hmm, in another thread I was actually asking if there’s a way to completely turn the fans off. Looks like I just found a workaround 🙂 I’ll wait for the update. Thanks! ---
**Author:** ![kabuto](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/kabuto/32/31102_2.png) [@kabuto](https://forum.snapmaker.com/u/kabuto)\ **Post date:** [October 6, 2026, 4:34pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/7 "2026-10-06T16:34:50Z")
OrcaSlicer allows you to control the top cover fan. I have this G-code in the machine. ;===== Automatic Top Cover Control based on filament type ===== {if filament\_type[initial\_extruder]==“PLA” || filament\_type[initial\_extruder]==“TPU” || filament\_type[initial\_extruder]==“PVA”} ; Strong cooling - Active extraction and cooling (prevents heat-related clogs) SET\_PURIFIER\_MODE MODE=1 DESIRE\_TEMP=42 ALARM\_TEMP=45 FAN\_SPEED=0.4 DELAY\_OFF=0 {elsif filament\_type[initial\_extruder]==“ABS” || filament\_type[initial\_extruder]==“ASA” || filament\_type[initial\_extruder]==“PC” || filament\_type[initial\_extruder]==“PA”} ; Heat retention - Heat retention and recirculation with carbon filter SET\_PURIFIER\_MODE MODE=3 DESIRE\_TEMP=45 FAN\_SPEED=0.4 DELAY\_OFF=600 {else} ; Default safe mode (PETG or other materials) SET\_PURIFIER\_MODE MODE=3 DESIRE\_TEMP=45 FAN\_SPEED=0.4 DELAY\_OFF=600 {endif} The problem is that previously I had it set to FAN\_SPEED=0.6, and it always stays at 60%, even if I lower the speed in Fluidd or directly on the printer to 40%. It quickly jumps back up to 60%. I haven’t tried 0.4 yet, but ideally, the fan speed should increase only when that temperature is reached. In my case, the chamber never exceeded 38°C, and the fan at 60% is too noisy for my liking. I have always printed with the IKEA enclosure closed and haven’t had any clogging or other issues. I hope that in future versions of Orca, this feature will be available by default. Best regards, and I hope this helps someone configure the Snapmaker Orca lid. ---
**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:** [October 19, 2026, 8:05pm UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/8 "2026-10-19T20:05:29Z")
I received my top cover. Mine does not turn off after print is done. I expect it to turn off instantly or stay on for like 30 something minutes in filter mode for material like ABS ASA that requires filtering. Just my setup thats failing or is this something not implmented? @Zoe_M ---
**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:** [October 20, 2026, 2:04am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/9 "2026-10-20T02:04:22Z")
Figured it out. Add to gcode DELAY\_OFF=0 For mode 1 and 2 And DELAY\_OFF=180 for mode 3 to let it filter ```auto {if min_vitrification_temperature <= 50} SET_PURIFIER_MODE MODE=1 DESIRE_TEMP=45 ALARM_TEMP=48 FAN_SPEED=0.60 DELAY_OFF=0 ; strong cooling {elsif min_vitrification_temperature < 70} SET \_PURIFIER_MODE MODE=1 DESIRE_TEMP=45 ALARM_TEMP=52 FAN_SPEED=0.60 DELAY_OFF=0 ; weak cooling {else} SET_PURIFIER_MODE MODE=3 DESIRE_TEMP=45 FAN_SPEED=0.3 DELAY_OFF=180 ; keep warm {endif} ``` Also now Orca support top cover too. > > > \# Description > > The U1 top cover has a purifier that can cool the chamber or keep… it warm. Snapmaker's own Orca sets the mode in the start G-code from the filaments on the plate. Mainline never sets it. > > This PR ports that, the rest of Snapmaker's start G-code changes and the matching filament softening temperatures from Snapmaker's Orca as of \[8931178229\](https://github.com/Snapmaker/OrcaSlicer/tree/89311782298309040ee28b9a183f33f0f5477b15) (main, 2026-10-15). Every value is copied from Snapmaker's Orca. I didn't tune anything. > > \## Purifier mode > > Snapmaker added a \`chamber\_cooling\_mode\` placeholder to \`GCode.cpp\` in Snapmaker/OrcaSlicer#504. It looks at the lowest softening temperature (\`temperature\_vitrification\`) of the filaments used, skipping filaments flagged \`filament\_is\_high\_temperature\`. The current commands are from Snapmaker/OrcaSlicer#1005. > > | Lowest softening temperature | Mode | Line | > |---|---|---| > | 50 or less | strong cooling | \`SET\_PURIFIER\_MODE MODE=1 DESIRE\_TEMP=42 ALARM\_TEMP=48 FAN\_SPEED=0.6 DELAY\_OFF=0\` | > | 51 to 70 | weak cooling | \`SET\_PURIFIER\_MODE MODE=1 DESIRE\_TEMP=45 ALARM\_TEMP=51 FAN\_SPEED=0.6 DELAY\_OFF=0\` | > | above 70 | keep warm | \`SET\_PURIFIER\_MODE MODE=3 DESIRE\_TEMP=45 FAN\_SPEED=0.6 DELAY\_OFF=600\` | > > Orca already has the lowest softening temperature of the used filaments as \`min\_vitrification\_temperature\`, and the BBL H2D and P2S start G-code uses it. So this is plain G-code with no C++ change. The block is right after \`M204 S10000\`, as in Snapmaker's version. > > Mainline has no \`filament\_is\_high\_temperature\`. Every filament Snapmaker flags has a softening temperature of 90 or more (90 for PCTG, 100 for ABS and ASA, higher for PA and PC), so leaving them in the minimum can't change the mode. > > \## Other start G-code changes > > Also from Snapmaker/OrcaSlicer#1005, in all four nozzle profiles. That PR gives no reasons, so the reasons below are my guesses. > > \- Pre-extrude the first tool after auto feed and flow calibration (\`M104\`, \`T\`, \`M109\`, \`SM\_PRINT\_PREEXTRUDE\_FILAMENT INDEX={initial\_extruder}\`). The other tools already get this the first time they're used, through the tool change G-code, so now the first tool starts primed too. > \- \`M107\` before \`G28 Z I140 J140\`, before \`DETECT\_BED\_PLATE\`, after \`WAIT\_CHAMBER\_TEMP\` and before bed leveling. Today the part fan runs at full speed through all of these. The U1 probes by touching the bed with the nozzle, and Snapmaker's own cleaning macros have commented-out lines that slow the nozzle fan while probing, so I think the fan was affecting probing. > \- \`M106 S255\` at the start of the deep nozzle clean, to turn the fan back on for the wipe, probably so the ooze sets before it's wiped off. > > Mainline's tool change G-code already has Snapmaker's pre-extrude step and PVA accel line. > > GitHub shows each start G-code as one long changed line, so I put a readable diff of it below. Click "Start G-code diff" to open it. It's the same in all four nozzle profiles, with trailing spaces trimmed. > > \ > \\Start G-code diff (click to expand)\\ > > \`\`\`diff > @@ -10,4 +10,12 @@ > M104 T{initial\_extruder} S140 > M204 S10000 > +;===== top cover purifier ===== > +{if min\_vitrification\_temperature \<= 50} > +SET\_PURIFIER\_MODE MODE=1 DESIRE\_TEMP=42 ALARM\_TEMP=48 FAN\_SPEED=0.6 DELAY\_OFF=0 ; strong cooling > +{elsif min\_vitrification\_temperature \<= 70} > +SET\_PURIFIER\_MODE MODE=1 DESIRE\_TEMP=45 ALARM\_TEMP=51 FAN\_SPEED=0.6 DELAY\_OFF=0 ; weak cooling > +{else} > +SET\_PURIFIER\_MODE MODE=3 DESIRE\_TEMP=45 FAN\_SPEED=0.6 DELAY\_OFF=600 ; keep warm > +{endif} > G28 X Y > DEFECT\_DETECT\_NOODLE\_FIRST > @@ -35,4 +43,10 @@ > M104 S0 T2 A0 > M104 S0 T3 A0 > + > +;==== 预挤出耗材 ===== > +M104 T{initial\_extruder} S{nozzle\_temperature\[initial\_extruder\]} > +T{initial\_extruder} > +M109 T{initial\_extruder} S{nozzle\_temperature\[initial\_extruder\]} > +SM\_PRINT\_PREEXTRUDE\_FILAMENT INDEX={initial\_extruder} > M104 T{initial\_extruder} S{nozzle\_temperature\[initial\_extruder\] - 90} > > @@ -45,10 +59,13 @@ > ROUGHLY\_CLEAN\_NOZZLE\_WITH\_DISCARD > MOVE\_TO\_XY\_IDLE\_POSITION\_EXTRUDER > +M107 > G28 Z I140 J140 > > ;===== 检测钢板 ================= > +M107 > DETECT\_BED\_PLATE > > ;===== 深度清洁喷嘴 ================= > +M106 S255 > G90 > G0 Z5 F10000 > @@ -73,4 +90,5 @@ > G0 Z5 F10000 > WAIT\_CHAMBER\_TEMP TIMEOUT=180 > +M107 > {if curr\_bed\_type=="High Temp Plate"} > G28 Z Z\_OFFSET -0.07 > @@ -81,4 +99,5 @@ > > ;===== 热床调平 ================= > +M107 > {if curr\_bed\_type=="High Temp Plate"} > ; Always pass \`ADAPTIVE\_MARGIN=0\` because Orca has already handled \`adaptive\_bed\_mesh\_margin\` internally > \`\`\` > > \ > > \## Not ported > > \- The fixed 11x11 \`BED\_MESH\_CALIBRATE\`. Mainline's adaptive mesh probes only the print area, so it's faster on small prints. Its \`Z\_OFFSET=-0.07\` condition is unchanged. > \- Removing the \`SET\_PRINT\_AUTO\_BED\_LEVELING ENABLE=1\` and \`SET\_TIME\_LAPSE\_CAMERA ENABLE=1\` lines that paxx12 added in #12219. Snapmaker's version doesn't have them. > \- \`M104\` in place of \`M109\` in the tool change G-code, also from Snapmaker/OrcaSlicer#1005. On the U1 firmware, \`T\` and \`M104\` don't wait for temperature, and \`SM\_PRINT\_PREEXTRUDE\_FILAMENT\` waits only the first time each tool is used (u1-klipper 1.6.0, \`klippy/kinematics/extruder.py\` and the \`INNER\_PREEXTRUDE\_FILAMENT\` macro). Snapmaker also sets its own \`tool\_change\_temprature\_wait\` setting, which mainline doesn't have. With \`M104\` in mainline, later tool changes could start printing before the nozzle is up to temperature. That needs its own test. > \- The \`Graphic Effect Plate\` branch of the \`G28 Z\` offset. Mainline has no such bed type. > > \## Filament softening temperatures > > The purifier mode is picked from \`temperature\_vitrification\`, so the U1 filament values matter now. Where Snapmaker's Orca has the same U1 preset, I used its value (\[filament profiles at 8931178229\](https://github.com/Snapmaker/OrcaSlicer/tree/89311782298309040ee28b9a183f33f0f5477b15/resources/profiles/Snapmaker/filament)): > > | Preset | Old | New | Mode | > |---|---|---|---| > | Snapmaker ABS @U1 (and ABS Benchy, same base) | 189 | 100 | keep warm, no change | > | Snapmaker ASA @U1 | 182 | 100 | keep warm, no change | > | Snapmaker PETG Translucent @U1 | 160 | 70 | keep warm -\> weak | > | Snapmaker PETG-CF @U1 | 178 | 70 | keep warm -\> weak | > | Snapmaker PLA Glow @U1 | 154 | 45 | keep warm -\> strong | > | Snapmaker PVA @U1 | 150 | 45 | keep warm -\> strong | > | Snapmaker TPU @U1 | 138 | 30 | keep warm -\> strong | > > Only PETG-CF's value was set in a U1 preset. Its 178 was added with the original U1 profiles in #10225, and Snapmaker has since changed it to 70 in its own Orca. The rest are inherited from the bundle's \`fdm\_filament\_\*\` presets, which #2939 set in 2023 for Snapmaker's earlier printers. #2939 raised them from 60 (PLA), 110 (ABS), 80 (PET) and 60 (TPU) to values near those materials' melting points, with no reason given. Snapmaker's Orca no longer has those presets. The other Snapmaker and Generic U1 presets that Snapmaker's Orca also has already match. > > Some mainline U1 presets have no U1 version in Snapmaker's Orca. Several of them inherit the bundle's 154 (PLA) or 138 (TPU), so a PLA or TPE print would get keep warm. For these I used the value Snapmaker gives the same material on the U1. In Snapmaker's Orca, every Snapmaker and Generic U1 preset of a material has the same value: 45 for PLA, 70 for PETG and 30 for TPU. These changes are in separate commits so they're easy to drop. > > | Preset | Old | New | Mode | > |---|---|---|---| > | Snapmaker PLA @U1 | 154 | 45 | keep warm -\> strong | > | Snapmaker PLA Eco @U1 | 154 | 45 | keep warm -\> strong | > | Snapmaker PLA Metal @U1 | 154 | 45 | keep warm -\> strong | > | Snapmaker PETG @U1 | 178 | 70 | keep warm -\> weak | > | Snapmaker TPE @U1 | 138 | 30 | keep warm -\> strong | > | Snapmaker TPU High-Flow @U1 | 138 | 30 | keep warm -\> strong | > | Snapmaker TPU 95A @U1 | 60 | 30 | weak -\> strong | > > Left as they are: > > \- Snapmaker PET @U1 (230) and PA-CF @U1 (203), keep warm. Snapmaker's Orca has no selectable U1 PET or PA-CF preset. > \- The Polymaker presets, which are third party. General PLA (62) and Tough PLA (55) get weak cooling where Snapmaker's U1 PLA presets get strong, and Silk PLA (45) gets strong. Snapmaker's Orca has the same values. > > \## Keys not copied > > These keys exist only in Snapmaker's Orca, so mainline would ignore them: \`filament\_is\_high\_temperature\`, \`graphic\_effect\_plate\_temp\`, \`graphic\_effect\_plate\_temp\_initial\_layer\`, \`tool\_change\_temprature\_wait\`, \`z\_hop\_when\_prime\`, \`ramming\_pressure\_advance\_value\`, \`filament\_flow\_support\`, \`printer\_flow\_support\`, \`top\_color\_penetration\_layers\`, \`bottom\_color\_penetration\_layers\`. > > I also left out a printer setting that has nothing to do with the purifier. Snapmaker turns \`support\_multi\_bed\_types\` off on the 0.2, 0.6 and 0.8 profiles, and mainline turned the bed type selector on in #15174. > > \## Firmware > > The two commands this PR adds exist from U1 firmware 1.3.0, based on the Snapmaker/u1-klipper releases 1.2.0 to 1.6.0. \`SM\_PRINT\_PREEXTRUDE\_FILAMENT\` is in all of them. \`SET\_PURIFIER\_MODE\` and every parameter used here are in 1.3.0 and later. On older firmware an unknown command only prints \`Unknown command:"..."\` (\`klippy/gcode.py\`) and the print continues. The 2.0 firmware source isn't published. > > The bundle version is bumped from 02.04.00.17 to 02.04.00.18. > > \# Screenshots/Recordings/Graphs > > None, profile G-code and filament values only. > > \## Tests > > Sliced the U1 0.4 nozzle profile through \`OrcaSlicer\_profile\_validator -s\` with three default filaments. The start G-code has the pre-extrude step and these purifier modes: > > \- Snapmaker PLA Basic @U1 gets strong cooling. > \- Snapmaker PETG-CF @U1 gets weak cooling. > \- Snapmaker ABS @U1 gets keep warm. > > I also printed on a U1 with the top cover using these profiles, and everything worked as expected. > > \[How to Download Pull Requests Artifacts for Testing\](https://www.orcaslicer.com/wiki/how\_to\_download\_pr\_artifacts) ---
**Author:** ![Zoe\_M](https://avatars.discourse-cdn.com/v4/letter/z/8491ac/32.png) [@Zoe\_M](https://forum.snapmaker.com/u/Zoe_M)\ **Post date:** [October 20, 2026, 2:52am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/10 "2026-10-20T02:52:53Z")
Thanks for the sharing the gcode. I also checked with the senior engineers. They explained that currently, for external circulation (e.g., when printing PLA), the exhaust fan will stop operating once the print is complete. For internal circulation, the recirculation fan will keep working for 10 more minutes after the print is complete. Best regards. ---
**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:** [October 20, 2026, 2:56am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/11 "2026-10-20T02:56:33Z")
~~Ohh, that’s definitely not happening for me. My top cover was on all night till I turned it off in morning. I used latest Snorca alpha build to send the print.~~ Fixed it. I had random klipper macro that i got from fb on auto unload that was messing with my `PRINT_END`. Thats what happen when you randomly get code from online, but this was before i started messing with klipper myslef, before i knew much about this stuff ---
**Author:** ![Zoe\_M](https://avatars.discourse-cdn.com/v4/letter/z/8491ac/32.png) [@Zoe\_M](https://forum.snapmaker.com/u/Zoe_M)\ **Post date:** [October 20, 2026, 5:15am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/12 "2026-10-20T05:15:11Z")
> [@ni42](#): > > Ohh, that’s definitely not happening for me. **My top cover was on all nigh** t till I turned it off in morning. > I used latest Snorca alpha build to send the print. The top cover will stay in standby mode (not completely off) after the print is complete, just like the U1 does when there is no print job. However, the fan should stop operating. So when you said “ **My top cover was on all nigh** t”, do you refer to the power status or the fan status? ---
**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:** [October 20, 2026, 5:17am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/13 "2026-10-20T05:17:18Z")
Exhaust was on the whole night. But like i said, I was able to fix it, I had custom macro that was messing with PRINT\_END. Even my led would not turn off after the print even though I have it enabled in the settings. ---
**Author:** ![dthoang](https://avatars.discourse-cdn.com/v4/letter/d/e47774/32.png) [@dthoang](https://forum.snapmaker.com/u/dthoang)\ **Post date:** [October 23, 2026, 5:09am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/14 "2026-10-23T05:09:42Z")
Regarding seal 1, read the instructions again carefully. The non-adhesive part should cover the gap between the door and the printer when the door is open. ---
**Author:** ![ginjeff](https://avatars.discourse-cdn.com/v4/letter/g/ce73a5/32.png) [@ginjeff](https://forum.snapmaker.com/u/ginjeff)\ **Post date:** [October 24, 2026, 1:43am UTC](https://forum.snapmaker.com/t/u1-top-cover-questions/43446/15 "2026-10-24T01:43:00Z")
I agree, it’s way too noisy at 60%. It should be adaptive and not run when it’s not needed. I just ran a simple test 4 minute print, PLA, and the chamber never went above 31C with the door closed and cover door attached. Really no need to have the exhaust fan running (to control temp, VOC might be a different discusson). It might also benefit from higher quality/lower noise fans.