Klipper max acceleration

When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer's intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper's maximum extrusion cross-section check. max acceleration in klipper May i know I had set 6000 as my max acceleration in Klipper. Do i need to set the settings of acceleration control in superslicer all to 0 ? For example, the perimeters, infill, bridge and etc. 2 10 10 comments Add a Comment derpinator12000 • 1 yr. ago Also check your machine limits.Log In My Account dh. cv; gw airmax 97 Nov 28, 2020 · Maximum Acceleration vs Acceleration Control Dear Team, say I set under Printer Settings -> Machine Limits -> Maximum acceleration (X, Z, Y) = 1000 mm/s² and also set under Print Settings -> Speed -> Acceleration Control -> Perimeters = 1800 mm/s² Maximum Acceleration vs Acceleration Control Dear Team, say I set under Printer Settings -> Machine Limits -> Maximum acceleration (X, Z, Y) = 1000 mm/s² and also set under Print Settings -> Speed -> Acceleration Control -> Perimeters = 1800 mm/s²Learning about and setting up the input shaper configuration on a klipper powered 3d printer, time to push things to the limitsIf you like what you see and w...Mar 15, 2018 · measurements were taken for 80 usteps/mm. (bare motors, no other mechanical parts) in all tests today the speed limit was at 1000 mm/s. in all old tests … air ambulance in royston today Maximum Acceleration vs Acceleration Control Dear Team, say I set under Printer Settings -> Machine Limits -> Maximum acceleration (X, Z, Y) = 1000 mm/s² and also set under Print Settings -> Speed -> Acceleration Control -> Perimeters = 1800 mm/s²One sick part of Klipper is that it has a 'tuning tower' build in. You can enter a command before the print starts so that it automatically increases/decreases a value every so many mm. So I did one for acceleration. Although it is hard to tell, when the gap starts to widen is where I need to limit acceleration. And then on to pressure advance. hockey cards tim hortons Klipper limits the torque on each stepper by virtue of limiting the acceleration of the print head. Enforcing acceleration at the print head naturally also limits the torque of the steppers that move the print head (the inverse is not always true). Klipper implements constant acceleration. The key formula for constant acceleration is: Nov 28, 2020 · Maximum Acceleration vs Acceleration Control Dear Team, say I set under Printer Settings -> Machine Limits -> Maximum acceleration (X, Z, Y) = 1000 mm/s² and also set under Print Settings -> Speed -> Acceleration Control -> Perimeters = 1800 mm/s² Max extruder acceleration #1444. Closed. ghost opened this issue on Mar 24, 2019 · 6 comments. chalet for sale hemsby belle aireRE: Maximum Acceleration vs Acceleration Control. Thank you for looking into this. I followed up also with some testing: If you e.g. set Printer Settings->Machine limits @1250 mm/s² and the Print Settings->Speed @1800 mm/s² then the second M204 line in the gcode will be generated as:. M204 S1250; adjust acceleration. @bobstro, this means that the configured maximum under "Machine limit" will ...When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer’s intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper’s maximum extrusion cross-section check. blue eyes white dragon 1st edition May 27, 2019 · Klipper will help you when you have an 8bit board, but IMHO it doesn't add much on 32bit boards like the Duet. The duet board should easily be able to drive a Cartesian build at high speed, but it depends on the mechanical quality of the frame whether this is possible Klipper limits the torque on each stepper by virtue of limiting the acceleration of the print head. Enforcing acceleration at the print head naturally also limits the torque of the steppers that move the print head (the inverse is not always true). Klipper implements constant acceleration. The key formula for constant acceleration is: 2022. 10. 18. ... The point at which the gap widens noticeably beyond 0.15 mm determines the maximum recommended acceleration. Remember that, by default, the ...Sep 20, 2018 · Not sure why different max speeds would be relevant. F=m*a, not speed here. This only if I went higher than lowest max speed for the print in the slicer. Say …A calibration script provides an estimate for max_accel parameter that should not create too much smoothing. Note that the max_accel as displayed by the calibration script is only a theoretical maximum at which the respective shaper is still able to work without producing too much smoothing. It is by no means a recommendation to set this acceleration for printing. atia vegas Max extruder acceleration · Issue #1444 · Klipper3d/klipper · GitHub Klipper3d / klipper Public Notifications Fork 4.1k Star 6k Code Issues 10 Pull requests 37 Actions Security Insights New issue Max extruder acceleration #1444 Closed ghost opened this issue on Mar 24, 2019 · 6 comments ghost commented on Mar 24, 2019This is the Ender 3 S1 running Klipper, printing at 150mm/s, 0.15 mm layer height with 3500 acceleration (realistically, it's probably printing at 100mm/s). ... ex patrol boats for sale uk Maximum Acceleration vs Acceleration Control Dear Team, say I set under Printer Settings -> Machine Limits -> Maximum acceleration (X, Z, Y) = 1000 mm/s² and also set under Print Settings -> Speed -> Acceleration Control -> Perimeters = 1800 mm/s²1 de jun. de 2022 ... I also attached a video where you can see the Ender 3 S1 running Klipper, printing at 150mm/s, 0.15 mm layer height with 3500 acceleration ... puppy farm doncaster Jan 24, 2022 · max_velocity in mm/s is the maximum speed Klipper allows the print-head to move. The higher the faster max_accel in mm/s^2 is the maximum acceleration Klipper …Feb 6, 2022 · Acceleration: 3000mm/s Prerequisites To install Klipper on Ender 3 S1, you need to have the following: Raspberry Pi (any Pi version will work) MainsailOS or FluiddPi – In this guide I will use MainsailOS and a Raspberry Pi 4. Stock Creality Ender 3 S1 3D Printer Quality Power Supply for your Raspberry Pi Type C cable which fits the Ender 3 S1 blvcks max_accel_to_decel: The currently set maximum accel to decel of the tool. acceleration to deceleration (mm/s^2). square_corner_velocity: The currently set square corner velocity. is the maximum velocity at which the tool may travel a 90 degree corner. Tip max_velocity, max_accel, max_accel_to_decel, and M204can also change max_accel.This is the Ender 3 S1 running Klipper, printing at 150mm/s, 0.15 mm layer height with 3500 acceleration (realistically, it's probably printing at 100mm/s). ... wolverhampton houses for sale Firmware Retraction¶ The following commands are available when the firmware_retraction config section is enabled 00 ;Setup machine max acceleration M203 X500 Instead, Klipper prefers human readable "extended G-Code commands" Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 ... Use a high speed (eg, 100mm/s), zero infill, and a coarse layer height (the layer height should be around 75% of the nozzle diameter). Make sure any "dynamic acceleration control" is disabled in the slicer. Prepare for the test by issuing the following G-Code command: SET_VELOCITY_LIMIT SQUARE_CORNER_VELOCITY=1 ACCEL=500 Then, add the endstop positions, rotation_distances and thermistor types from the ender 5 2020 config. Note that I had to change the stepper_z direction pin from PC5 to !PC5; the default klipper acceleration is a bit tight for the E5, it may be better to limit max_velocity to 150, and max_accel to 2000.Firmware Retraction¶ The following commands are available when the firmware_retraction config section is enabled 00 ;Setup machine max acceleration M203 X500 Instead, Klipper prefers human readable "extended G-Code commands" Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 ...Head moves left while priming and then starts printing. Optional. Maximum acceleration and feedrates are set. Retraction acceleration set. Z bed and extruder ... how to shrink brain cysts naturally M193: Set Laser Cooler Temperature M200: Set Filament Diameter M201: Print Move Limits M203: Set Max Feedrate M204: Set Starting Acceleration M205: Set Advanced Settings M206: Set Home Offsets M207: Set Firmware Retraction M208: Firmware Recover M209: Set Auto Retract M211: Software Endstops M217: Filament swap parameters M218: Set Hotend Offset stagecoach 85 bus timetable Klipper limits the torque on each stepper by virtue of limiting the acceleration of the print head. Enforcing acceleration at the print head naturally also limits the torque of the steppers that move the print head (the inverse is not always true). Klipper implements constant acceleration. The key formula for constant acceleration is:Jan 24, 2022 · max_velocity in mm/s is the maximum speed Klipper allows the print-head to move. The higher the faster max_accel in mm/s^2 is the maximum acceleration Klipper …The default is to use max_velocity for # max_z_velocity. max_z_accel: # This sets the maximum acceleration (in mm/s^2) of movement along # the z axis. It limits the acceleration of the z stepper motor. The # default is to use max_accel for max_z_accel.Klipper Per-axis acceleration Features ky438945 April 22, 2021, 12:28pm #1 I think Klipper would be improved if acceleration limits could be set per axis. This would be of particular help on "bed slingers" (lower y acceleration to limit forces on bed + printed object) but seems to be of more general use. This change might even simply the code? request cvpixelbuffer for frame returned 2020. 12. 5. ... Learning about and setting up the input shaper configuration on a klipper powered 3d printer, time to push things to the limitsIf you like ... chemdawg clones Max Weber is credited as one of the three founders of sociology, but his most well-known contribution was his thesis that combined economic and religious sociology. This thesis proposed that ascetic Protestantism was associated with the ris...2021. 3. 11. ... Recap of last weeks livestream, finding out your printers max acceleration, why use MZV over recommended input shaper, and is tape ok for ...Jan 1, 2021 · Klipper - 5000 Acceleration, 100mm/s. Tried pushing my Ender 3 to the max after pressure advance and input shaper calibration. Acceleration set to 5k, print speed …Mar 24, 2019 · I guess it&#39;s due to the overall acceleration set to 700 (very heavy bed in a i3 scenario). Is t... Skip to content Toggle navigation. Sign up Product Actions. … social studies for primary 5 third term Dec 10, 2018 · Now i define max_extrude_only_velocity and max_extrude_only_accel to my normal maximum settings for the whole pinter in my cfg. Now the retract is quite faster …Aug 8, 2019 · Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 S<value>: M201 X500.00 Y500.00 Z100.00 …Maximum Acceleration vs Acceleration Control Dear Team, say I set under Printer Settings -> Machine Limits -> Maximum acceleration (X, Z, Y) = 1000 mm/s² and also set under Print Settings -> Speed -> Acceleration Control -> Perimeters = 1800 mm/s² om foundation A calibration script provides an estimate for max_accel parameter that should not create too much smoothing. Note that the max_accel as displayed by the calibration script is only a theoretical maximum at which the respective shaper is still able to work without producing too much smoothing. It is by no means a recommendation to set this acceleration for printing. kijiji in alberta This was the ultimate test for the Ender 6 running the BIQU H2 extruder. It was printed at 100mm/s with 4000 acceleration and took ~7 hours. I wasn’t expecting the print quality to be this good considering the speed it was printed at. All the moving parts work as expected, and I was able to move the 0.3 mm tolerance indicator which is decent.Head moves left while priming and then starts printing. Optional. Maximum acceleration and feedrates are set. Retraction acceleration set. Z bed and extruder ...Max is older, he’s a drunk, and he can’t stop popping pills; he’s in pretty rough shape. Does he have what it takes to make Max Payne 3 a worthy successor to the Max Payne franchise? Game On correspondent Alex Rubens spent some time wanderi... euromillions hotpicks prizes It's recommended to let klipper handle acceleration for this reason. It is possible to change the max acceleration "on-the-fly" but you should only do so in (for example) your start_print macro, before extrusion begins, so that the changing acceleration doesn't cause jerks that affect print quality.Firmware Retraction¶ The following commands are available when the firmware_retraction config section is enabled 00 ;Setup machine max acceleration M203 X500 Instead, Klipper prefers human readable "extended G-Code commands" Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 ... Klipper - 5000 Acceleration, 100mm/s. Tried pushing my Ender 3 to the max after pressure advance and input shaper calibration. Acceleration set to 5k, print speed 100mm/s for everything, except first layer. If it actually manages to reach 100mm/s on such short walls is up for debate, but it's still BLAZING fast.Jul 27, 2021 · Klipper limits the torque on each stepper by virtue of limiting the acceleration of the print head. Enforcing acceleration at the print head naturally also limits the torque of the steppers that move the print head (the inverse is not always true). Klipper implements constant acceleration. The key formula for constant acceleration is: A magnifying glass. It indicates, "Click to perform a search". in. oe sufc shop Log In My Account dh. cv; gw1 day ago · Jerk X & Y should be at 7. Acceleration for X, Y, Z should be set to 700. You can go directly into your menu on your printer, select the control setting, then ‘motion’ you …Jun 2, 2019 · When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder … carmarthen livestock market report max_accel_to_decel: The currently set maximum accel to decel of the tool. acceleration to deceleration (mm/s^2). square_corner_velocity: The currently set square corner velocity. is the maximum velocity at which the tool may travel a 90 degree corner. Tip max_velocity, max_accel, max_accel_to_decel, and M204can also change max_accel. RE: Maximum Acceleration vs Acceleration Control. Thank you for looking into this. I followed up also with some testing: If you e.g. set Printer Settings->Machine limits @1250 mm/s² and the Print Settings->Speed @1800 mm/s² then the second M204 line in the gcode will be generated as:. M204 S1250; adjust acceleration. @bobstro, this means that the configured maximum under "Machine limit" will ...Max Weber is credited as one of the three founders of sociology, but his most well-known contribution was his thesis that combined economic and religious sociology. This thesis proposed that ascetic Protestantism was associated with the ris... best new post punk bands Max is older, he’s a drunk, and he can’t stop popping pills; he’s in pretty rough shape. Does he have what it takes to make Max Payne 3 a worthy successor to the Max Payne franchise? Game On correspondent Alex Rubens spent some time wanderi...When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer’s intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper’s maximum extrusion cross-section check. The firmware max speed should be the highest mechanical speed you can reach without skipping. The reason I bring up volumetric is flow is that it lets you determine the max speed you will actually be printing lines at. Whatever that speed is should be the one you use to tune your acceleration values with the test print. 2 bed houses for rent in shepshedIn this section you set your maximum accelerations and velocity. ... These are the highest values that klipper will allow regardless of what you may have ...When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer's intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper's maximum extrusion cross-section check. sutton carp syndicate Anycubic i3 mega S printerHotend: e3d v6, direct MK4 Extruder: BMGBearings: 7 MSM Drivers: 2209 + 2208 Native table without additional processing (ala adhesi... Firmware Retraction¶ The following commands are available when the firmware_retraction config section is enabled 00 ;Setup machine max acceleration M203 X500 Instead, Klipper prefers human readable "extended G-Code commands" Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 ... Recap of last weeks livestream, finding out your printers max acceleration, why use MZV over recommended input shaper, and is tape ok for the accelereometer?...Then, add the endstop positions, rotation_distances and thermistor types from the ender 5 2020 config. Note that I had to change the stepper_z direction pin from PC5 to !PC5; the default klipper acceleration is a bit tight for the E5, it may be better to limit max_velocity to 150, and max_accel to 2000. contact cheshire police 2022. 8. 13. ... The max velocity is more limited at 45° than at 90°. But now, when the toolhead reaches maximum velocity, there is always at least one motor ...2022. 10. 18. ... The point at which the gap widens noticeably beyond 0.15 mm determines the maximum recommended acceleration. Remember that, by default, the ...The firmware max speed should be the highest mechanical speed you can reach without skipping. The reason I bring up volumetric is flow is that it lets you determine the max speed you will actually be printing lines at. Whatever that speed is should be the one you use to tune your acceleration values with the test print. Aug 8, 2019 · Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 S<value>: M201 X500.00 Y500.00 Z100.00 …Jan 19, 2023 · Step 1 -> (500 + 10000) / 2 = 5250. Step 2 -> Accel, Amax X, Amax Y set to 5250 mm/s^2. Now, let’s assume that we have noticed some print quality issues related … yard space to rent northamptonshire Klipper Bed Level Macros v2 a guest Jun 20th, 2022 4,633 0 Never Add comment Not a member of Pastebin yet? Sign Up , it unlocks many cool features! text 6.81 KB | None | 0 0 raw download clone embed print report [gcode_macro M600] description: Starts process of Filament Change gcode: {% if printer.extruder.temperature < 180 %}in prusaslicer Printer Settings>Machine Limits there are 3 settings for acceleration control. you should let printer.cfg handle acceleration limits but you should also enter the same values in slicer and tell slicer to use those values for print time estimates.The LDO input shaper toolkit provides all the necessary parts for performing Klipper input shaper calibration with minimal hassle. For detailed information regarding klipper input …When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer’s intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper’s maximum extrusion cross-section check. professor messer comptia a+ 1101 notes When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer’s intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper’s maximum extrusion cross-section check.Jan 24, 2022 · max_velocity in mm/s is the maximum speed Klipper allows the print-head to move. The higher the faster max_accel in mm/s^2 is the maximum acceleration Klipper … vintage cap gun uk Max is older, he’s a drunk, and he can’t stop popping pills; he’s in pretty rough shape. Does he have what it takes to make Max Payne 3 a worthy successor to the Max Payne franchise? Game On correspondent Alex Rubens spent some time wanderi... the heights west bromwich rent Basic Klipper configuration editor Performance graph displaying key parameters extracted from the Klipper logs. PID Tuning of heater_generic · Issue #5310 · Klipper3d/klipper. The open-source Klipper firmware for 3D printers has been the choice of By PID tuning, your 3d printer can heat the specific elements to .Jul 21, 2021 · When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer's intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper's maximum extrusion cross-section check. When Klipper is commanded to make significant changes to the extrusion rate it will plan out the corresponding changes to velocity, acceleration, and extruder movement - which is not the slicer’s intent. The slicer may even command excessive extrusion rates to the point that it triggers Klipper’s maximum extrusion cross-section check.2020. 12. 5. ... Learning about and setting up the input shaper configuration on a klipper powered 3d printer, time to push things to the limitsIf you like ...Here my gcode start in cura: Profile for Creality CR10S PRO V2 M201 X500.00 Y500.00 Z100.00 E5000.00 ;Setup machine max acceleration M203 X500.00 Y500.00 Z10.00 E50.00 ;Setup machine max feedrate M204 P500.00 R1000.00 T500.00 ;Setup Print/Retract/Travel acceleration M205 X8.00 Y8.00 Z0.40 E5.00 ;Setup Jerk M220 S100 ;Reset Feedrate falkirk houses to rent Aug 8, 2019 · Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 S<value>: M201 X500.00 Y500.00 Z100.00 …Checking the Setup To test everything works correctly, run the command ACCELEROMETER_QUERY in your klipper console. If everything is correct, you should see some measurements from the accelerometer on the console output. Calibration The easiest way to perform calibration is to simply run the command SHAPER_CALIBRATE in your klipper console. xccdg Head moves left while priming and then starts printing. Optional. Maximum acceleration and feedrates are set. Retraction acceleration set. Z bed and extruder ...Firmware Retraction¶ The following commands are available when the firmware_retraction config section is enabled 00 ;Setup machine max acceleration M203 X500 Instead, Klipper prefers human readable "extended G-Code commands" Cura: M201, M203, M204, M205: The new Creality definitions set these in the start Gcode, Klipper only supports M204 ...Learning about and setting up the input shaper configuration on a klipper powered 3d printer, time to push things to the limitsIf you like what you see and w...12 de mai. de 2020 ... A pseudo acceleration (in mm/s^2) controlling how fast the. toolhead may go from acceleration to deceleration. It is used to.MAX OUT ACCELERATION - Find your printers limit with input shaper! NERO 3D 41.9K subscribers Join Subscribe 1.7K 58K views 1 year ago Recap of last weeks livestream, finding out your printers... gendex sensor repair Then, add the endstop positions, rotation_distances and thermistor types from the ender 5 2020 config. Note that I had to change the stepper_z direction pin from PC5 to !PC5; the default klipper acceleration is a bit tight for the E5, it may be better to limit max_velocity to 150, and max_accel to 2000.A magnifying glass. It indicates, "Click to perform a search". in. oeThis is the Ender 3 S1 running Klipper, printing at 150mm/s, 0.15 mm layer height with 3500 acceleration (realistically, it's probably printing at 100mm/s). ...Mar 24, 2019 · Max extruder acceleration · Issue #1444 · Klipper3d/klipper · GitHub Klipper3d / klipper Public Notifications Fork 4.1k Star 6k Code Issues 10 Pull requests 37 Actions Security Insights New issue Max extruder acceleration #1444 Closed ghost opened this issue on Mar 24, 2019 · 6 comments ghost commented on Mar 24, 2019 virtual console wads download Max extruder acceleration · Issue #1444 · Klipper3d/klipper · GitHub Klipper3d / klipper Public Notifications Fork 4.1k Star 6k Code Issues 10 Pull requests 37 Actions Security Insights New issue Max extruder acceleration #1444 Closed ghost opened this issue on Mar 24, 2019 · 6 comments ghost commented on Mar 24, 2019Klipper limits the torque on each stepper by virtue of limiting the acceleration of the print head. Enforcing acceleration at the print head naturally also limits the torque of the steppers that move the print head (the inverse is not always true). Klipper implements constant acceleration. The key formula for constant acceleration is:The above TUNING_TOWER command instructs Klipper to alter the pressure_advance setting on each layer of the print. Higher layers in the print will have a larger pressure advance value set. ... If this occurs, either use a lower acceleration value or disable pressure advance. Once pressure advance is tuned in Klipper, it may still be useful to ...The default is to use max_velocity for # max_z_velocity. max_z_accel: # This sets the maximum acceleration (in mm/s^2) of movement along # the z axis. It limits the acceleration of the z stepper motor. The # default is to use max_accel for max_z_accel. grey eagle buffet menu Basic Klipper configuration editor Performance graph displaying key parameters extracted from the Klipper logs. PID Tuning of heater_generic · Issue #5310 · Klipper3d/klipper. The open-source Klipper firmware for 3D printers has been the choice of By PID tuning, your 3d printer can heat the specific elements to . log cabins with hot tubs norfolk Jul 27, 2021 · Klipper limits the torque on each stepper by virtue of limiting the acceleration of the print head. Enforcing acceleration at the print head naturally also limits the torque of the steppers that move the print head (the inverse is not always true). Klipper implements constant acceleration. The key formula for constant acceleration is: international piano competitions 2021 As a rule we typically don't allow the Slicer to set acceleration (or decel) values and instead use the values set in Klipper. That said, the SET_VELOCITY_LIMIT command can change those values in real-time during printing. If you really want to allow the Slicer to set those values (and you have it configured to emit acceleration gcodes) then I ...Recap of last weeks livestream, finding out your printers max acceleration, why use MZV over recommended input shaper, and is tape ok for the accelereometer?...Now i define max_extrude_only_velocity and max_extrude_only_accel to my normal maximum settings for the whole pinter in my cfg. Now the retract is quite faster than befor. It was the whole time blocking from the standart settings of klipper when these two settings are not definded. dying light 2 auto hdr