As an experienced people with motors, give me an educated guess : what torque do you think I need ?
An experienced person would never guess, they would measure the torque required.
Under the same wattage, what motor will give me more torque and speed, DC or Stepper ?
Question cannot be answered without providing both power and speed.
You're forgetting several important factors before you can determine what kind of motor (and gearbox, possibly) is required.
the amount of weight you've placed on the desktop and
how fast you want the desktop to raise and lower.
With whatever motor and drive system you may choose, you also have to consider that lowering the desktop may require negative torque (braking) but this depends upon what type of mechanical system IKEA provides with the desk.
Making any assumptions about what is required to do this will most certainly be wrong.
Unfortunately I do not have the desk now, I wanted to pre-order the motor, I will have the desk only on august.
Regarding the questions:
There will be probably 10-20kg on the desk.
And 60 RPMs should be fast enough (it is about the same speed a person will crank it manually).
I'm looking for a ballpark estimation to start with, not something very accurate.
I've used that kind of desk before, they have a lot of friction in the mechanism to prevent it descending
if you sit on it. Yes, wait till you have your desk and can measure the torque, in the upwards direction
with full load - the friction is not guessable, you need to measure.
Then double that figure for good measure and select a gear motor with that torque on the output, perhaps
100 to 200rpm output speed is reasonable, I remember having to crank the handle a lot....
If we are allowed to guess, here's mine: an accu screwdriver/drill. The accu could be a perfect power buffer. Its charger can probably not handle the current that the motor needs, but the charger would just take care of charging when you don't run the motor.
The windshield wiper has probably the right rpm on the axis. The screwdriver has probably too high speed without an additional gearbox and using it on half effect would just creat heat on wrong place.
