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中圖分类号：TU855 文献标识码：A 文章编号：1009-914X（2013）29-025-01
（1）Aim
I am doing a project ：converting a old CNC machine into 3D printer for accurate 3D printing. In this article I will briefly share my experience on how to improve the printing quality via changing the critical Skeinforge settings on the software Replicator G.
（2） Four main steps undertaken
There are more than 40 parameters in Skeinforge but there are only 4 parameters（parts） that makes up the foundation of a product profile ：
2.1 Set the Layer Thickness：
The old name for this is called “layer height”. A 3D printer prints a sample by drawing （with plastic PLA） the first base layer， moving up a little distance then drawing another layer. After thousands of times and putting down enough layers the printing process is finished.
We can change the layer thickness value from 0.1mm to 0.5mm based on different working conditions and printing demands. That means if the printing head is flexible enough and moves fast then the thinner layer is better for satisfied result .For instance， the layer height applied in the newest 3D printer Replicator2 is only 0.1mm but in my project based on the actual overloading ability of the engraving machine.Last，as the layer height decreases， the resolution increases.
2.2 Set the Flow Rate：
This is also called PWM （ Pulse Width Modulation） and means how fast the extruder motor is turning.
One thing new users easily misunderstand is that flow rate is only about how fast the extruder motor turns and how fast the length of plastic goes the extruder. But it is not the same as how much plastic comes out of the nozzle .
.An example to undertand this： when we have a skeinforge profile with a 255 flow rate on the 2.70 filament and we try using this profile with 3.10mm filament， the result will be disappointed. The reason is that a 2.70mm filament only has a 5.7mm? cross section area but a 3.1mm filament has another 7.5mm? area. This means 30% more plastic per length of filament.
To test the minimum flow rate， in the control panel there can type values in the ”Motor Speed （PWM）” box .Then temperature or the color of your filament or the filament quality– these would not have huge differences it is good to be aware of those to ensure a better Flow Rate setting.
2.3 Set the Feed Rate：
The feed rate speed means how fast the X，Y，Z axis and the printing head moves. In other words it means the X，Y，Z axis motor moving speed. To test the maximum moving speed is time consuming. However it is necessary when the technicians want to make sure the printings is fast but without losing quality. The ‘standard’ MakerBot profiles are usually around 25-30 mm/s and the value I choose is 10mm/second. Beyond this level the x-axis motor will be jerked which leads to a shifting may position compared to the original design.
Last thing，only turning up the feed rate does not really help sample building but when combining it with other two things： turning down the layer height and using a smaller nozzle， the building quality can be increased to a new level.
2.4 Set the Infill
Fill plug-in defines the way inside of the object that will be filled.. For the Infill settings the first things to be considered are Shells on Alternating Solid Layer and Shells on Base .The first is used to add layers outside of the object and the second is for extra layer on the object base.
It is useful to choose a value of Infill Solidity （ratio），ie. Having the value as 1， the object will be 100% full of plastic， with this set to 0.3 only 30% of the inside will be plastic and rest will be empty space. It is very useful because printers do not have to fill the object with plastic as all the outsides are 100% covered so inside it can be hollow. Note that a higher infill solidity ratio gives a higher strength but costs more time， which only used in building important components. A lower ratio is more practical when printer only needs to print some testing samples .
Conclusion
For an old one or a converted 3D printer from old CNC machine like the one I use， these four steps must be carefully followed. Only based on these other improving strategies become useful and could be applied later.
（1）Aim
I am doing a project ：converting a old CNC machine into 3D printer for accurate 3D printing. In this article I will briefly share my experience on how to improve the printing quality via changing the critical Skeinforge settings on the software Replicator G.
（2） Four main steps undertaken
There are more than 40 parameters in Skeinforge but there are only 4 parameters（parts） that makes up the foundation of a product profile ：
2.1 Set the Layer Thickness：
The old name for this is called “layer height”. A 3D printer prints a sample by drawing （with plastic PLA） the first base layer， moving up a little distance then drawing another layer. After thousands of times and putting down enough layers the printing process is finished.
We can change the layer thickness value from 0.1mm to 0.5mm based on different working conditions and printing demands. That means if the printing head is flexible enough and moves fast then the thinner layer is better for satisfied result .For instance， the layer height applied in the newest 3D printer Replicator2 is only 0.1mm but in my project based on the actual overloading ability of the engraving machine.Last，as the layer height decreases， the resolution increases.
2.2 Set the Flow Rate：
This is also called PWM （ Pulse Width Modulation） and means how fast the extruder motor is turning.
One thing new users easily misunderstand is that flow rate is only about how fast the extruder motor turns and how fast the length of plastic goes the extruder. But it is not the same as how much plastic comes out of the nozzle .
.An example to undertand this： when we have a skeinforge profile with a 255 flow rate on the 2.70 filament and we try using this profile with 3.10mm filament， the result will be disappointed. The reason is that a 2.70mm filament only has a 5.7mm? cross section area but a 3.1mm filament has another 7.5mm? area. This means 30% more plastic per length of filament.
To test the minimum flow rate， in the control panel there can type values in the ”Motor Speed （PWM）” box .Then temperature or the color of your filament or the filament quality– these would not have huge differences it is good to be aware of those to ensure a better Flow Rate setting.
2.3 Set the Feed Rate：
The feed rate speed means how fast the X，Y，Z axis and the printing head moves. In other words it means the X，Y，Z axis motor moving speed. To test the maximum moving speed is time consuming. However it is necessary when the technicians want to make sure the printings is fast but without losing quality. The ‘standard’ MakerBot profiles are usually around 25-30 mm/s and the value I choose is 10mm/second. Beyond this level the x-axis motor will be jerked which leads to a shifting may position compared to the original design.
Last thing，only turning up the feed rate does not really help sample building but when combining it with other two things： turning down the layer height and using a smaller nozzle， the building quality can be increased to a new level.
2.4 Set the Infill
Fill plug-in defines the way inside of the object that will be filled.. For the Infill settings the first things to be considered are Shells on Alternating Solid Layer and Shells on Base .The first is used to add layers outside of the object and the second is for extra layer on the object base.
It is useful to choose a value of Infill Solidity （ratio），ie. Having the value as 1， the object will be 100% full of plastic， with this set to 0.3 only 30% of the inside will be plastic and rest will be empty space. It is very useful because printers do not have to fill the object with plastic as all the outsides are 100% covered so inside it can be hollow. Note that a higher infill solidity ratio gives a higher strength but costs more time， which only used in building important components. A lower ratio is more practical when printer only needs to print some testing samples .
Conclusion
For an old one or a converted 3D printer from old CNC machine like the one I use， these four steps must be carefully followed. Only based on these other improving strategies become useful and could be applied later.