Understanding how print quality is affected by speed.
So for my first post i thought i'd share some knowledge i found through reading forum ports, testing with various settings in relation to speeds, and having an keen interest in the science behind things. And please bare in mind i am no expert, no engineer, just someone who has a keen interests and want to know why things do what they do,
In general its pretty simple, the faster you go the more your quality suffers. Simple right? Not really...
First lets look at the motions your printer makes as it actually moves.
When you're x carriage makes a move, its actually 3 motions happening pretty quickly, Jerk, Acceleration and then a move at a constant speed. Then when it comes to a stop it does the same 3 motions but in reverse, it will move at a constant speed, slow itself down then jerk to a stop position.
Jerk is the movement needed to overcome the friction between the x-carriage bearings and the smooth rods they run on.
Acceleration is the rate at which is will accelerate up to the desired speed
Constant speed is, well, it moves at the desired constant speed.
Artifacts such as banding and uneven edges on corners can be caused by movement in the x axis due to it not being rigid, slack in belts, not proper leveling the bed flat and running parallel with the x axis...the list goes on. But this post is going to concentrate how speed affect prints, and what you could do to increase the quality and the speed of your prints.
The easiest way in my opinion, is to make your x carriage lighter, make your setup rigid and reduce the friction between moving parts, lots of friction is bad and a little is good, no friction at all would end badly, but more on that later.
The more weight on the carriage when it tries to slow down equals more energy spent trying to slow down the mass of the carriage to a specific point. The lighter the carriage, the less energy is required to slow it down. As a general rule of thumb its a trade off between speed and weight which dictates how accurately your carriage will stop at a given point (in a perfect world where belt tension and other things are set correctly) So if you can make your x and y carriage lighter they will be able to move quicker while still being able to stop closer to a specified point.
Rigidity plays a big part in z banding and being able to print at higher speeds, vibration in any of your axis' will lead to artifacts in your printing. After installing a z brace mod and taking my time to make sure my machine was square and tightened up so you could try move the top of the machine and it wont budge, it helped improve the quality of my prints instantly, which then made subsequent mods much easier to apply and dial in.
Now friction, its a tricky one because too much friction cause pre-mature wear on bearings, rods and other items. But yet if the rods are too slippery well your be left with prints that have jagged corners which can look a little like banding or over extrusion on the walls of objects from where the belts have stopped moving but the print head carries on every so slightly, taking up any small amount of slack on your belt. But when you find an oil that has just the right amount of lubricity (is that a word?) it makes the world of a difference. You'll notice that where the printer turns at the corner of a wall or shell it will look slightly more defined and really does help with the accuracy of the moving parts.
So thats about all i fancy writing up at the moment, it's bloody hot here at the moment and sitting next to a computer and a printer enclosure printing abs doesnt help things.
I hope you've took away a bit of a better understanding about the speeds actually affect your print. Understand the various aspects will really help you fine tune, recognize and diagnose small artifacts or imperfections in your prints.
Again none of this is professional opinion, im by no means a scientist, engineer or some car salesman from Louisiana. If you have any questions go ahead and shoot them my way, if i can help in any way i shall do!
Take it easy.
Daz
In general its pretty simple, the faster you go the more your quality suffers. Simple right? Not really...
First lets look at the motions your printer makes as it actually moves.
When you're x carriage makes a move, its actually 3 motions happening pretty quickly, Jerk, Acceleration and then a move at a constant speed. Then when it comes to a stop it does the same 3 motions but in reverse, it will move at a constant speed, slow itself down then jerk to a stop position.
Jerk is the movement needed to overcome the friction between the x-carriage bearings and the smooth rods they run on.
Acceleration is the rate at which is will accelerate up to the desired speed
Constant speed is, well, it moves at the desired constant speed.
Artifacts such as banding and uneven edges on corners can be caused by movement in the x axis due to it not being rigid, slack in belts, not proper leveling the bed flat and running parallel with the x axis...the list goes on. But this post is going to concentrate how speed affect prints, and what you could do to increase the quality and the speed of your prints.
The easiest way in my opinion, is to make your x carriage lighter, make your setup rigid and reduce the friction between moving parts, lots of friction is bad and a little is good, no friction at all would end badly, but more on that later.
The more weight on the carriage when it tries to slow down equals more energy spent trying to slow down the mass of the carriage to a specific point. The lighter the carriage, the less energy is required to slow it down. As a general rule of thumb its a trade off between speed and weight which dictates how accurately your carriage will stop at a given point (in a perfect world where belt tension and other things are set correctly) So if you can make your x and y carriage lighter they will be able to move quicker while still being able to stop closer to a specified point.
Rigidity plays a big part in z banding and being able to print at higher speeds, vibration in any of your axis' will lead to artifacts in your printing. After installing a z brace mod and taking my time to make sure my machine was square and tightened up so you could try move the top of the machine and it wont budge, it helped improve the quality of my prints instantly, which then made subsequent mods much easier to apply and dial in.
Now friction, its a tricky one because too much friction cause pre-mature wear on bearings, rods and other items. But yet if the rods are too slippery well your be left with prints that have jagged corners which can look a little like banding or over extrusion on the walls of objects from where the belts have stopped moving but the print head carries on every so slightly, taking up any small amount of slack on your belt. But when you find an oil that has just the right amount of lubricity (is that a word?) it makes the world of a difference. You'll notice that where the printer turns at the corner of a wall or shell it will look slightly more defined and really does help with the accuracy of the moving parts.
So thats about all i fancy writing up at the moment, it's bloody hot here at the moment and sitting next to a computer and a printer enclosure printing abs doesnt help things.
I hope you've took away a bit of a better understanding about the speeds actually affect your print. Understand the various aspects will really help you fine tune, recognize and diagnose small artifacts or imperfections in your prints.
Again none of this is professional opinion, im by no means a scientist, engineer or some car salesman from Louisiana. If you have any questions go ahead and shoot them my way, if i can help in any way i shall do!
Take it easy.
Daz
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