Editing Improving precision
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If you are producing sloppy drawings, or good ones that you want to be better, you may need to do one or more of the following: | If you are producing sloppy drawings, or good ones that you want to be better, you may need to do one or more of the following: | ||
'''Alignment:''' | '''Alignment:''' | ||
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* '''Check egg alignment.''' Make sure that the object (which we'll call an "egg" even if it's a light bulb or a golf ball) being plotted is very well centered on the egg axis. Use the "Raise pen, turn off motors" setup mode to turn your object by hand, and make sure that it is as concentric as possible. | * '''Check egg alignment.''' Make sure that the object (which we'll call an "egg" even if it's a light bulb or a golf ball) being plotted is very well centered on the egg axis. Use the "Raise pen, turn off motors" setup mode to turn your object by hand, and make sure that it is as concentric as possible. | ||
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* '''Increase tension.''' Compressing the plunger spring further pushes the "egg" against the egg-cup of the egg-motor, improving contact. This generally helps ''up until'' the tension starts to create excess drag-- for example when the spring is fully compressed. | * '''Increase tension.''' Compressing the plunger spring further pushes the "egg" against the egg-cup of the egg-motor, improving contact. This generally helps ''up until'' the tension starts to create excess drag-- for example when the spring is fully compressed. | ||
− | * '''Check egg alignment | + | * '''Check egg alignment 2.''' Turn off the motors, raise the pen, and move the pen all the way left and right around the egg. You're looking to have the pen tip be the same distance from the egg surface all the way round. |
'''Machine setup:''' | '''Machine setup:''' | ||
− | * ''' | + | * '''Check contact.''' The "egg" needs to make good contact with the egg-motor. There should not be any slippage between the two, or the egg will gradually work its way out. Even if there is not slippage, there can be apparent "backlash" (direction-dependent lag) when the egg-motor turns back and forth. It may help to clean and dry the "egg" and/or the polyurethane egg cup. For super-precision work you may want to experiment with different egg cup designs, or even screw down or glue your object to the egg-motor shaft. |
− | * '''Check | + | * '''Check for drag on the plunger.''' If the plunger is not able to turn easily, then it will provide drag to the "egg." If the tension is too high, the O-ring is rubbing on the back bushing, or the thin nylon washer is not present, there can be increased drag. |
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− | * ''' | + | * '''Reduce lateral play in the plunger.''' See Appendix B of the assembly instructions for hints on how to do this. |
* '''Use a smaller/shorter pen.''' The pen arm grips your pen very close to the bottom of the pen. While this generally gives better precision, gripping the pen below the center of mass means that there will be more sway, particularly when the pen has been lifted or is being lowered. | * '''Use a smaller/shorter pen.''' The pen arm grips your pen very close to the bottom of the pen. While this generally gives better precision, gripping the pen below the center of mass means that there will be more sway, particularly when the pen has been lifted or is being lowered. | ||
* '''Check for drag on the pen.''' The pen should only lightly touch the surface that it's drawing on. If you use a stiff hinge, or otherwise arrange things such that there's heavy downward force, it can create excess drag at the egg-pen interface. | * '''Check for drag on the pen.''' The pen should only lightly touch the surface that it's drawing on. If you use a stiff hinge, or otherwise arrange things such that there's heavy downward force, it can create excess drag at the egg-pen interface. | ||
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'''Surfaces and Pens:''' | '''Surfaces and Pens:''' | ||
− | * '''Plot on a smooth surface.''' | + | * '''Plot on a smooth surface.''' No matter what you do, Egg-Bot will never produce good results on a tennis ball. Golf balls are okay, though. |
* '''Clean your medium before plotting.''' If you remove surface dust and oils before drawing, you'll get a sharper plot. In particular, certain types of pens will show fingerprints-- areas where the pen does not make as strong as a mark, where the object has been handled. | * '''Clean your medium before plotting.''' If you remove surface dust and oils before drawing, you'll get a sharper plot. In particular, certain types of pens will show fingerprints-- areas where the pen does not make as strong as a mark, where the object has been handled. | ||
* '''Maintain your pen(s).''' Clean them frequently (if applicable.) And, ''don't let them dry out''. | * '''Maintain your pen(s).''' Clean them frequently (if applicable.) And, ''don't let them dry out''. | ||
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'''Eggbot Control Settings:''' | '''Eggbot Control Settings:''' | ||
− | * '''Slow down the pen speed.''' The faster the pen is moving, the more vibration (and thus slop) you'll have when the pen stops moving. By slowing the speed at which the motors turn, you'll improve your drawings | + | * '''Slow down the pen speed.''' The faster the pen is moving, the more vibration (and thus slop) you'll have when the pen stops moving. By slowing the speed at which the motors turn, or the servo lifts/drops the pen, you'll improve your drawings. The correct speed will depend upon your medium (egg shells, glass, etc) and your pens -- you'll need to experiment. Often you can raise the pen much faster than you can lower it. |
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