Ender 3 stepper drivers

Adjusting stepper motor drivers

There are many things to take in count when we speak about stepper motor drivers. But we don’t want to go in too many details, instead, in this article, I will talk about the basics. I will explain how they work and what we need to know to not damage them or our motherboard. Also, I will provide some tips that I learned on my own skin during my experience.

What is VREF

The literal translation of the term is a voltage reference. Stepper motors drivers have a device designed to maintain an accurate, low noise, constant output current. This is the exact description of what the driver does. The driver is the electronic device that takes care of guiding the stepper motor through the translation of the signals(an electric current) that are given to it by a processor.

Stepper motors move differently from normal electric motors, in fact, they aren’t very fast. They move slowly but are more powerful and very precise.

The calibration that we are going to do on the drivers of these motors is going to affect the VREF and the amount of current that the motors will release. The more precise this value is, the more the motor movement will be optimized. The idea here is to have enough power to not lose steps but also to not overheat the motors.

Ender 3 VREF TMC2208 / TMC2209

If you have an Ender 3 you surely know that the motherboard has integrated stepper drivers which means that we cannot replace them. So the first step would be doing a motherboard upgrade, which has lots of benefits. Having a motherboard with non-integrated stepper drivers, mean that we can easily change them if one burns, also adding the more advanced drivers will make our print more precise and silent.

The maximum settable stepper current for the stepper motors(NEMA 17) on the Ender 3 is 2.0A, but we will want to use a lower value. Something like 0.9 or 0.8. I will be using a TMC2208 stepper driver. The TMC2208 has a max output of 1.2A RMS. Reading the formula below, we see our VREF should be set at 0.96V.

The typical formula to determinate if goes like this:

-> Vref = Amax x RMS <-

VREF = 0.8 x 1.2 = 0.96

Amax = maximum number of Ampere the motor can handle

RMS = is the value of the maximum output on the drivers

How to calculate VREF

Every driver’s family reacts in different ways and some require different calculations and formulas to get the perfect voltage.

For example, the formula for the A4988 is :

VREF = Amax x 8 x Rsense;

Rsense – The A4988 boards are based on the Pololu board and therefore use a resense value of 0.05. 

We saw that 0.96V is the ideal setting value for our driver. That said, we can slightly change this value with a margin error of 0.1. My axis drivers are set to 1V without showing any sign of suffering or heating.

How to adjust VREF

Items Needed

Now that the theoretical part is solved let’s move on to the practice.

For this part, the use of a 1.5mm ceramic screwdriver is recommended.

We are sure that no amateur/novice has this kind of tool in their workshop because it is quite technical. I will explain how to make the exact same adjustment using a normal iron screwdriver.

First, we have to go to analyze our drivers and locate the adjustment screw, it has exactly the appearance of a star screw.

The motherboard of some 3D printers is equipped with removable drivers, others have the drivers directly on the board and are less recognizable. The one thing in common that they have is the typical VREF adjustment gear.

If we are installing new drivers we must get the direction right, on the back of the drivers we will see some writings right next to each pin. The pin name must be in correspondence with the connector on the board. In the picture below we can see that different drivers have the VREF gear in different places and this shouldn’t be used as criteria to determine the right orientation, instead, we should use the pin names.

We turn on the electric multimeter and bring it on the 2V scale, in direct current (DC), at this point we place the negative (black) on the negative of our power supply or on the negative of our board (on the arrival of the black wire that brings current to our electronic card).

We put the red test lead in contact with the screw we identified earlier and read the value. Since we are using an iron screwdriver we must unplug everything from the board except for the driver to avoid burning the board! After that, we need to increase/decrease the voltage rotating slowly the gear.

To increase power, the screw must be turned counterclockwise, contrary to what experience and habit tell us.

Now you just have to “tweak”, gradually decreasing the rotation, until you find the right voltage.

Many times, however, this approach to driver regulation, due to keeping us very “safe” does not give the expected results, in fact, it could happen that the extruder still loses a few steps. We only speak of an extruder because the loss of steps in the axis movement motors, is a symptom of some mechanical hitch, therefore it is preferable to check that everything flows smoothly rather than “pulling the neck” on the motors.

Brutal method

If the extruder still loses a few steps, it is possible to switch to brutal adjustment. Following the procedure above (switch off each time before placing the iron screwdriver on the driver screw). Set the tester on Ampere and turning the screw one-eighth of a turn, always counterclockwise to increase the power, increase the power until the loss of the steps has disappeared.

From experience we can say that already at 1,2A all the step losses will disappear and you will be on a voltage/amperage well supported by the motor. Make sure, however, that you have a fan for the drivers as the power increase corresponds to more heat.

We recommend that you monitor the temperatures of the drivers and motors, at least in the first 2 or 3 hours of printing. The working temperature of the drivers should not exceed 60 °C, as well as that of the motors of 50 °C. You can easily monitor the temperature at regular intervals with a digital infrared thermometer.

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Summary

Article Name

How to calculate VREF

Description

The literal translation of the term is a voltage reference. Stepper motors drivers have a device designed to maintain an accurate, low noise, constant output voltage. This is the exact description of what the driver does. The driver is the electronic device that takes care of guiding the stepper motor through the translation of the signals(an electric current) that are given to it by a processor.

Author

Danut Andres

Publisher Name

3DprintGuides

Publisher Logo

Hi folks,

I've had my Ender 3 for several years and it's been a really good machine, but of late it's simply not been able to work well. I've upgraded the extruder, rebuilt the hot end, all kinds of things but, today I finally noticed that the real issue may be the stepper motor. I came across this while noticing that the motor wasn't even running properly forward while doing the 'test line' it runs on the left hand side of the print bed before a print. No material was extruded on the test line. I noticed the motor snapping back and forth, but not smoothly running forward. 

I then tried a filament extrude/retract using the change filament function and, quite simply, it couldn't do either. The filament runs free and extrudes quite nicely if I press it through by hand. Even with the extruder not under tension, the motor still isn't doing what it's supposed to.

Is the solution just to replace the extruder motor? They're not particularly expensive - but a lot of forums say that they really don't wear out - yet mine just doesn't seem to run properly anymore. All the other steppers work just fine.

Here's a vid of what it's doing:

https://www.flickr.com/photos/[email protected]/50973778528/in/album-72157704505315475/

More info - replaced the motor, same issue. Replaced the control cable to the motor, same issue. Switched the control cable to one of the other motors (Z Axis)  it then stuttered and behaved like the extruder motor.

Bad control board? Something else?

Questions & Answers about Creality Stepper Motor

Pose a question about this product to customers who have already purchased the item. Please forward any other order-related questions to our Customer Service Team.

• What is the the difference between 42-34 and 42-34 roundshaft

  1 Answer, last answered on 07 July 2021

  • Andrew

    07 July 2021

    Customer Service

• Does this (42-40) have the D shape shaft for tightening a grub screw onto or is it round?

  1 Answer, last answered on 21 May 2021

  • Andrew

    21 May 2021

    Customer Service

• What is the shaft diameter of the 42-60 dual-shaft motor?

  1 Answer, last answered on 17 May 2021

  • Andrew

    17 May 2021

    Customer Service

• What current is the 42-48 dual shaft rated for? Thank you

  1 Answer, last answered on 17 May 2021

  • Andrew

    17 May 2021

    Customer Service

• Is the dual shaft stepper (y-axis) for an Ender 5 Pro the same as the Ender 5 ?

  1 Answer, last answered on 03 May 2021

  • Andrew

    03 May 2021

    Customer Service

Show all answers

Customer Reviews

What does this board do?

This is a budget silent board from Creality themselves. It is a decent low-cost alternative to our EZBoard. This board is supported in our Unified 2 firmware multiple 3D printer models (see below). If a printer is not specifically listed below, it is not officially supported by our firmware.

Features/Details

• Genuine Creality V4.2.7 board with Trinamic TMC2225 Drivers
• Guaranteed Genuine STM32 CPU – With manufacturers swapping out STM32 CPUs in favor of knock-off chips, we are opening and checking EVERY board before shipment to ensure it has a genuine STM32 CPU on it.
• 512K Flash Memory with EEPROM support
• This board has a bootloader that allows updating the firmware from the MicroSD card
• Uses MicroUSB Cable to Connect (not included)
• Works with the below printers:
  • CR-10
  • CR-10S
  • CR-10 Mini
  • CR-10S Mini
  • CR-10 S4
  • CR-10S S4
  • CR-10 S5
  • CR-10S S5
  • Ender 3/3 Pro
  • Ender 3 V2
  • Ender 5/5 Pro
    • Ender 5 machines will likely need our LCD EMI filter board due to how Creality designed this board.
• Free firmware available from TH3D Studio – Ships with Testing Firmware, you will need to flash it for your machine with a SD card and a Computer
• Compatible with EZABL, EZOut Filament Sensor Kits, and BL Touch Probes
• VREF is set with the pots next to each driver – Make sure to set the VREF for your machine. Refer to Creality documentation for the VREFs for their printers.

CR-10 Model Support Notes (Read this BEFORE buying for a CR-10 Series)

CR-10 (Regular, Mini, S4 S5)

• Models with 2 separate Z Motor connectors need the Dual Z Motor Adapter Addon
• MOSFET needed for the bed if your machine does not already have one (addon above)

CR-10S (Regular, Mini, S4 S5)

• Needs Creality Dual Cable LCD Adapter Board if you do not have the EXP3 header on your LCD.
• If you have the EXP3 header on your LCD use 1 cable to connect from the EXP3 to our board and you will then not need the dual adapter board.
• Models with 2 separate Z Motor connectors need the Dual Z Motor Adapter Addon
• MOSFET needed for the bed if your machine does not already have one (addon above)
• Does NOT work with Touch Screen Models

Important Information

• Make sure to have an active cooling fan over the board to keep it cool. The Trinamic drivers run warmer than boards with the “standard” (aka 4988 series) drivers.
• On some machines, the EMI filter board addon is required, specifically Ender 5 machines.
• Because the stepper drivers are not connected to UART for control (they are in standalone mode) Linear Advance does not work on this board.  If you are not going to use Linear Advance (most people do not) then this does not apply to you.
  • If you want to use Linear Advance we recommend using our EZBoard instead as it works correctly with Linear Advance.

Warranty Information

3 Months Warranty -  Our warranty covers any and all defects with the product. If your product fails or has problems within the warranty period you can contact our support team by using the Contact Us link.

Damage/Failure due to improper installation, improper usage, failure resulting from an issue with the machine the product is installed on, 3rd party products connected to our product, and/or modification of the product are not covered under warranty.

Share your thoughts!

Let us know what you think...

The Creality Ender 3 is part of the new wave of budget 3D printers, available for less than $250 from many online retailers. For the money, it’s hard to complain about the machine, and it’s more than suitable for anyone looking to get make their first steps into the world of FDM printing. But there’s certainly room for improvement, and as [Simon] shows in a recent blog post, a little effort can go a long way towards pushing this entry-level printer to the next level.

The first step was to replace the printer’s stepper drivers with something a bit more modern. Normally the Ender 3 uses common A4988 drivers, but [Simon] wanted to replace them with newer Trinamic drivers that offer quieter operation. Luckily, Trinamic makes a drop-in replacement for the A4988 that makes installation relatively easy. You’ll need to change out a few caps and remove some resistors from the board to make everyone play nice, but that shouldn’t pose a challenge to anyone who knows their way around a soldering iron.

Beyond quieter running steppers, the Trinamic TMC2208 drivers also offer direct UART control mode. Of course the Ender’s board was never designed for this, so the MCU doesn’t have enough free pins to establish serial communications with the three drivers (for the X, Y, and Z axes). But [Simon] realized if he sacrificed the SD card slot on the board, the six pins that would free on the controller could be cut and rewired to the driver’s UART pins.

Combined with the Klipper firmware, these relatively minor modifications allows him to experiment with printing at speeds far greater than what was possible before. Considering the kind of headaches that a ~$200 printer would have given you only a few years ago, it’s impressive what these new machines are capable of; even if it takes a few tweaks.