Shifted layers

Shifted Layers / Offset Layers / Missed Steps

P#	Cause	Effect/Symptoms	Solution
1	Driver current is too low	Lower current causes lower motor torque. Rapid starts and stops can exceed the torque of the motor. Note that torque declines rapidly with speed.	Before increasing the driver current – first make sure it is not too hight (see the next item). Increase the driver current by turning the trim pot on the driver 1/8 turn clockwise. Use a non-conductive (ceramic) screwdriver so you don't cause a short. Do not turn it too far.
2	Driver current is too high	When stepper motor drivers overheat they do a thermal-shutdown. This shutdown can be of any duration from milliseconds to some larger part of a second. This causes steps to be missed. Symptoms: - Driver chip is burning hot. You can tell by a very quick and very careful touch. Don't burn yourself! If you can touch it for a second or more without burning yourself it is probably OK, but don't burn yourself! - Motor may also be very hot - On a large motor (Nema 23) you may hear repeated clunk sounds when the driver re-engages.	There are several possible solutions: - Reduce the motor current by turning the trim pot on the driver 1/8 turn counter clockwise. - Add a fan to cool the drivers. The fan may need to be a powerful one, wired to be always on. - Add heat syncs to the drivers in addition to the fan.
3	Belt too Loose	- Belt slips - Excess play - Heated bed carriage: looser belt tension when the heated bed has been hot for some time.	Tighten the belt.
4	Belt too Tight	A belt that is too tight can cause binding.	Loosen the belt slightly.
5	Loose Set Screw/Grub Screw	The drive pulley spins on the shaft a random amount when under load. To diagnose: draw a line on the stepper shaft and the end of the drive pulley. See if the pulley has shifted in relation to the pulley after a layer shift.	There are two things that should be done to make sure the drive pulleys do not come loose: - Grind a flat on the stepper shaft where the set screw will contact it. - Add a drop of nail polish to the set screw threads before installing the set screw. This acts like a removable thread lock compound.
6	Belt or Bearing is binding	- Move the axes by hand with the power disconnected to feel if there are any sticky spots. - You may need to temporarily remove a belt to feel the movement more easily without the motor vibration.	- Remove any obstruction. - Lubricate bearings or guides.
7	Speeds are too high	- High travel speeds create greater forces that must be overcome by the motors. This combined with acceleration can lead to an offset layer. - 8-bit controllers have a limited total step rate that varies depending on their total processing load. Exceeding this step rate can cause uneven stepping and missed steps.	- Lower travel and print speeds in your slicer. - When commissioning a printer: use speeds at or below 50. - The default speeds, jerk, and acceleration in firmware are often too high.
8	Acceleration is too high	- The motor's torque at a given speed must be greater than the force needed to accelerate or decelerate the mechanism at a given acceleration rate and maximum speed. - If the torque required is higher than the motor can supply at that speed then layers will be shifted. - Note that a stepper motor's torque is much lower at high speed. (give link here) - Note that a stepper motor can not instantly go from a stop to a high speed, it must be ramped up or it will just squeal and vibrate without moving.	Note that maximum acceleration rates vary for each printer implementation, and by the speeds used (there is less torque at high speed). (Can we give some sane defaults for commissioning?) Decrease acceleration in firmware. Low Marlin acceleration settings: DEFAULT_MAX_FEEDRATE {500, 500, 2, 45} // (mm/sec) DEFAULT_MAX_ACCELERATION {180,180,10,200} DEFAULT_ACCELERATION 60 DEFAULT_RETRACT_ACCELERATION 60 (Give other references)
9	Shifted layers in the Y axis (Shifted layers in any heavy axis)	- For printers that move the print bed in the Y axis there is much more moving mass for that axis' motor to overcome. - Too much acceleration in that direction causes an offset. - This may happen more with some objects than others, depending on the geometry that is being printed – the Y axis may have to start and stop and reverse direction more.	Decrease Y axis Acceleration/Jerk settings in firmware. See above.
10	Jerk Settings too high	Jerk is a firmware setting for the amount of instantaneous speed change that is allowed without using acceleration. The Jerk setting is used primarily at the very beginning and end of a movement. (How to diagnose?)	(Settings to change?)
11	Step rate too high for stepper motor	- Stepper motors have a limited speed that varies by model. As noted above, the faster the speed, the lower the torque. Above a certain speed it will loose enough torque to loose it's place. (See here.)	- Lower the travel or print speeds. - Use a larger pulley if the steps per mm are more than needed. For instance if the steps per mm for that axis is greater than needed, then a larger pulley will drive it faster, and a lower step rate can be used. - Use a higher voltage. A higher voltage allows a higher motor RPM. (Whereas higher current gives higher torque). You must not exceed the voltage rating of the controller and drivers, and more cooling will be required.
12	Step rate too high for 8-bit controller (like Arduino)	- 8-bit controllers can only output steps at a limited total rate for all steppers combined. - Delta printers require much more processing power to compute the paths - Graphic displays require more processing power than simple text displays. - Symptoms are: stuttering/jittering motors while traveling at high speed, or in a rounded contour, or with high detail.	- Get a 32-bit controller like a Smoothie or Azteeg, or ? And never have this issue again. (give links) - Do not use a graphic display with a Delta printer using an 8-bit controller - Lower travel and print speeds - Lower microstepping where not needed. For example if the extruder steps per MM is > 500 with 16 microsteps, then lowering microsteps to 8 would result in a much lower step overhead without sacrificing print quality. - Some drivers will deliver 32 microsteps, when only 16 microsteps are usually required, change the jumpers and change steps per mm in firmware. - Use a larger pulley as noted above. - Note that a lower microstep setting can make a motor run louder. - Use a different firmware. Repetier is reported to allow a higher step rate if “quad-stepping” is turned on.
13	Mid-band Resonance	Stepper motors have resonant frequencies where it is difficult to drive them - they loose torque and may not accelerate through these bands, causing missed steps.	- Use lower speeds - Use larger pulleys if resolution permits it - Use external DSP based stepper motor drivers. These allow driving the motor faster and quieter, and using a higher voltage. - Note that more powerful motors like Nema-23 are more prone to mid-band resonance in the RPM ranges used for 3D printers (and they are louder), so a DSP based motor driver is recommended.
14	USB Communication Problems	USB data may not be evenly streamed from the computer (particularly Windows computers) causing a stall in the print. If the stall happens at the wrong time there can be a layer shift.	- It is very highly recommended to always print from an SD card! - If you must print using a USB port, then make sure the cable is of high quality. Cheap USB cables can allow more interference. - Make sure the USB cable does not run near a source of interference – like stepper motor wires. - Add a toroid to the USB cable (give source) - Shield the wiring. (See this thread.)
15	Axis is too heavy for motor torque	A heavy axis requires a motor with higher torque.	- Lighten the axis as much as possible - Use a higher driver current - Use a more powerful motor / higher current / external drivers rated at higher current. See mid-band resonance above.
16	Wiring Problem	- Wire may be loose - Bare wires may be shorting	DO NOT WORK ON MOTOR WIRING WITH THE POWER ON. Disconnecting a motor wire while the power is on can blow the driver chip. - Make sure all wires are tight and insulated where needed. - Make sure the motor wires are connected correctly. There are two separate coils in a stepper motor. Use an ohm meter to determine which wires are in each pair (the wire colors may not be standard). The polarity is not important (except if wired backwards the motor will rotate backwards), however the pairs must not be mixed – the pair for one coil are together – say on pin 1 and 2, then the pair for the next coil are together next to the first pair – say on pin 3 and 4.
17	Electrical Interference	Unshielded wires can cause communications problems	See this thread
18	Nozzle Hits the Print	- Extrusion not calibrated and the nozzle hits the extra material. - Nozzle hits a curled edge.	- Calibrate the extruder (give link) - Do not use a fan with ABS – that makes curling worse. - In Slic3r: turn on “z-lift” – on the Printer Settings, Extruder 1 Page. - In Cura: turn on “z hop when retracting” on the Expert Settings page.
19	Something loose	- Something is loose and causing a bind.	- Make sure there is not loose wiring that could snag. - Make sure the print bed/glass is firmly attached.
20	Endstop Triggered	Something is triggering an endstop	Make sure there is nothing loose that triggers an endstop
21	Decay Mode	Drv8825 needs fast decay mode for some motors, or they run rough at low speeds	(Give link)
22	Driver is bad	Rarely a driver works intermittently	Switch the driver with one from another axis, and see if the problem follows. If you switched the X and Y axis drivers, then print the same part rotated 90 degrees, since the part orientation may matter.
23	Bad Microcontroller	Lightning strike caused microcontroller to be flaky. Realoading firmware and replacing drivers did not help.	Replace the Arduino board (one case found like this).
24	Printer dimensions incorrect	Printer dimensions in firmware do not match the dimensions in your slicer	The firmware may trigger a limit, or an endstop may be triggered if the printer dimensions are incorrect in firmware (one case found like this).