Post by Adam on Apr 25, 2020 13:49:30 GMT
Theme: Seeing a Man About a Horse
A quick note that this will be my last lesson for a while. The next couple of lessons will take me a few weeks to complete. The topic will be Designing and Printing Figures/People. I am researching and experimenting on this topic. It will take me a few weeks to be ready for those lessons, but I want everyone to know that they are coming. Some of the technology is still in it's infancy, so finding a formula that works is where I am spending most of my time. I expect this to be two lessons, but that could change.
On to lesson 4. This week we will learn about some of the more advanced techniques that can be employed when printing a more complicated or delicate model. We build upon the previous lessons, especially lesson 3. I do not plan to rehash those lessons, so it is important that you have absorbed them before diving into this one.
A good example of an elaborate or delicate model would be O-scale (and certainly smaller) figures of people and animals. The arms, legs, hair and other things extending from the object or those pieces that are smaller in size need help to print properly. Melted plastic can’t print a shape very well in thin air. It needs support. So, we will talk mostly about the various types of support tricks that can be used. I wont be walking through the printing process this week (that was last week). Instead, I will talk about each of the tools and some other more advanced considerations. The 3D printing world has invented several kinds including Supports, Walls, Rafts and Brims. We will also touch on re-scaling, temperature (adding humidity to the discussion). Lastly, we will briefly touch on the cleanup process. With all of these techniques, I can only teach you so much. You will learn the most by trial and error. Use this as a reference.
Our Object
Firstly, let me talk about the object I will use today to help illustrate the lesson. I wanted some horses for the layout and for my livestock cars. I found this one to the perfect one: www.thingiverse.com/thing:597082. Again, I didn't design this, so please check it out on thingiverse.com to acknowledge the person who designed it. I selected this model because it has some of the intricate aspects that will help illustrate the lesson. Here it is in the slicing software.
Re-Scaling
The first thing that you may or may not notice is that this horse is big. I think it is about G-Scale. Much bigger than we want. So, we need to start by getting it down to O scale. Fortunately, this is easy. In Flashprint (the slicing SW that comes with the Flashforge products), you just click the scale button on the left. You have several options here. You can change the scale using percentage or by changing the mm count of any of the three axis. You can also choose to scale each axis differently by un-checking the “Uniform Scaling” option. This is all about preference. For me, I usually just change the height of the object and leave Uniform Scaling on. Depending on how the object is oriented, this is usually the Z axis. Everyone on this forum has a sense for what O-Scale looks like, so I wont get into the numbers in detail here. Take a ruler to your layout to get an idea. For my horse, I went with a 40mm height (measured from the lowest point of the object to the highest, the top of the mane in the horse's case). BTW, I find measuring objects in millimetres as opposed to the American system of measurement to be easier as most of the SW works in metrics.
Orienting the Model
OK, so now we have our object and it is properly scaled. The next consideration is how we should orient it on the bed for printing. Here are some things to consider.
Is there a good flat surface that can sit on the bed? The horse sort of has this on the bottom of its hooves.
Is the object tall or long in shape? Is the bulk of it skewed to one part of the object? If you think about the horse, you will see that it has thin legs and a big body. It is, in a way, top-heavy. Plastic isn't heavy, but you get the point.
Will the printer need to print a lot of things in thin air? Remember, hot plastic needs t be supported well to properly print the object. The horses body has to be printed between the front and back legs.
So, does it make sense to print the horse like it is standing up, like this? Or does it make better sense to print it on it's side, like this.
I prefer the latter. Printing the horse on it's side will reduce the amount of supports need to be printed and cleanup is a bit easier. I will cover those things later. The real answer may only come after trial and error.
Supports
Next up is something called supports. Think of this as scaffolding for the parts of the object that are floating in thin air. The slicing software will basically add these into the model to support these parts of the object. Most slicing software will do something called Auto-Supports. It can detect those parts of the object and automatically add in the support pieces. You often can also draw the supports yourself, but I have found that to be tricky and the auto-support function works more than good enough.
Walls
When all else fails, you may need to go extreme and use a wall. A wall is what it sounds like. This scaffolding completely surrounds the object, touching the outside edge of the objects all the way around. For the more delicate or complex objects this may become your only choice. Personally, I have only had to go to this extreme only twice. I hate walls. They are a pain in the butt to clean up and often the object will break when you do so. Only use this when nothing else will work.
Rafts & Brims
In Lesson 3 I covered Brims. Again, think of this as the brim of a hat. Rafts and Brims are similar. Both are tricks you can use to expand the object to print bed surface area. The more surface area, the better adhesion to the bed and the more success you will have. There are distinct differences however.
A brim will expand the surface area outward (it radiates outward) around the part(s) of the object that sits flat on the bed. If you want to simply create a surface area that for the entire area of the object, you want to use a Raft. If you have many small surface areas, a Raft is a better choice. For example, if you decided that you want to print the horse standing up on its four legs, a raft would be a good choice. When in doubt, go with a raft.
Adhesion Factors (Bed Leveling, Temperature/Humidity, Orientation, Filament Failure)
The most important thing to get right with a print is adhesion to the bed. An object that is being printed needs to adhere well to the bed. If not, it can warp or worse, move/fall off the bed. Either would be a failure and you would need to restart. Failures typically occur because of one of three things. I added a couple more that are more rare. As with all of these tips, trial end error will help you figure out what works.
1. Bed Leveling: First and foremost, your print bed needs to be level to print something properly. Every printer has a different process. Newer ones have auto-leveling. I highly recommend spending the extra dollars on a printer with that feature. Either way, check your printer manual on how to properly level the bed.
2. Temperature and/or Humidity: Both the print head and the print bed heat up. The print head heats up to melt the plastic. The print bed heats up to hold the plastic down as the object prints. The temperature you want to set the bed to depends on a number of factors. The primary factor is the type of plastic. When you do your slicing, the software will automatically set the print head and print bed temperature parameters according to the type of plastic selected. These are preset by the manufacturer and generally are universally agreed. However, sometimes you need to change the temperature. The most common reason for needing to change it is relative humidity. The ideal conditions for a good print with PLA is somewhere around 30 to 40% humidity. Too much (above 50%) is not good and too little is not good. In the summer, printing in the basement (with my dehumidifier running) is easy. However, fellow New Englanders know, and my dry hands can attest, that the air gets very dry in the winter. Increasing the heat of the bed and print head along with enclosing the print makes up for that lower humidity.
3. Orientation: Another reason a print can go wrong is because an object is just poorly oriented on the bed. Always take extra care when you are in the slicing software to make sure the flat side of the object is on the bed flat. Most software will have a “put it on the bed” type of option. This makes it easy.
4. Filament Failure: This is rare, but does happen. If you have filament that has sat around for a bit in a very dry or very humid (either end of the spectrum) it can become brittle. Filament usually comes with a silica packet to absorb excess moisture. I have found that if I keep it in the plastic packaging with that silica and in the box, it lasts a very long time. Store it carefully is all I am saying.
5. Nozzle Failure: All kinds of other failures can occur, but luckily they are rare. One of the less rare is if the print head comes loose. Sometimes that leads to plastic flooding the head, leading to the need to replace it. Luckily print heads (also known as nozzles) are pretty inexpensive. I bought a small bag of about 10 for something like $20. Good to have extras on-hand.
Cleanup
This part of the lesson will be very short. If you printed with any type of scaffold and/or a brim or raft, you will need to clean it up. As modelers, I know you are all in-tune to this process. The sheet of plastic parts that come with model airplanes and cars remind me of the same process. Craft snipers/scissors and/or knives are your friend here. Some people also use a little bit of fine sandpaper. Once cleaned up, they are ready to paint.
Other Photos
Here are some other pictures I took along the way for this lesson.
A quick note that this will be my last lesson for a while. The next couple of lessons will take me a few weeks to complete. The topic will be Designing and Printing Figures/People. I am researching and experimenting on this topic. It will take me a few weeks to be ready for those lessons, but I want everyone to know that they are coming. Some of the technology is still in it's infancy, so finding a formula that works is where I am spending most of my time. I expect this to be two lessons, but that could change.
On to lesson 4. This week we will learn about some of the more advanced techniques that can be employed when printing a more complicated or delicate model. We build upon the previous lessons, especially lesson 3. I do not plan to rehash those lessons, so it is important that you have absorbed them before diving into this one.
A good example of an elaborate or delicate model would be O-scale (and certainly smaller) figures of people and animals. The arms, legs, hair and other things extending from the object or those pieces that are smaller in size need help to print properly. Melted plastic can’t print a shape very well in thin air. It needs support. So, we will talk mostly about the various types of support tricks that can be used. I wont be walking through the printing process this week (that was last week). Instead, I will talk about each of the tools and some other more advanced considerations. The 3D printing world has invented several kinds including Supports, Walls, Rafts and Brims. We will also touch on re-scaling, temperature (adding humidity to the discussion). Lastly, we will briefly touch on the cleanup process. With all of these techniques, I can only teach you so much. You will learn the most by trial and error. Use this as a reference.
Our Object
Firstly, let me talk about the object I will use today to help illustrate the lesson. I wanted some horses for the layout and for my livestock cars. I found this one to the perfect one: www.thingiverse.com/thing:597082. Again, I didn't design this, so please check it out on thingiverse.com to acknowledge the person who designed it. I selected this model because it has some of the intricate aspects that will help illustrate the lesson. Here it is in the slicing software.
Re-Scaling
The first thing that you may or may not notice is that this horse is big. I think it is about G-Scale. Much bigger than we want. So, we need to start by getting it down to O scale. Fortunately, this is easy. In Flashprint (the slicing SW that comes with the Flashforge products), you just click the scale button on the left. You have several options here. You can change the scale using percentage or by changing the mm count of any of the three axis. You can also choose to scale each axis differently by un-checking the “Uniform Scaling” option. This is all about preference. For me, I usually just change the height of the object and leave Uniform Scaling on. Depending on how the object is oriented, this is usually the Z axis. Everyone on this forum has a sense for what O-Scale looks like, so I wont get into the numbers in detail here. Take a ruler to your layout to get an idea. For my horse, I went with a 40mm height (measured from the lowest point of the object to the highest, the top of the mane in the horse's case). BTW, I find measuring objects in millimetres as opposed to the American system of measurement to be easier as most of the SW works in metrics.
Orienting the Model
OK, so now we have our object and it is properly scaled. The next consideration is how we should orient it on the bed for printing. Here are some things to consider.
Is there a good flat surface that can sit on the bed? The horse sort of has this on the bottom of its hooves.
Is the object tall or long in shape? Is the bulk of it skewed to one part of the object? If you think about the horse, you will see that it has thin legs and a big body. It is, in a way, top-heavy. Plastic isn't heavy, but you get the point.
Will the printer need to print a lot of things in thin air? Remember, hot plastic needs t be supported well to properly print the object. The horses body has to be printed between the front and back legs.
So, does it make sense to print the horse like it is standing up, like this? Or does it make better sense to print it on it's side, like this.
I prefer the latter. Printing the horse on it's side will reduce the amount of supports need to be printed and cleanup is a bit easier. I will cover those things later. The real answer may only come after trial and error.
Supports
Next up is something called supports. Think of this as scaffolding for the parts of the object that are floating in thin air. The slicing software will basically add these into the model to support these parts of the object. Most slicing software will do something called Auto-Supports. It can detect those parts of the object and automatically add in the support pieces. You often can also draw the supports yourself, but I have found that to be tricky and the auto-support function works more than good enough.
Walls
When all else fails, you may need to go extreme and use a wall. A wall is what it sounds like. This scaffolding completely surrounds the object, touching the outside edge of the objects all the way around. For the more delicate or complex objects this may become your only choice. Personally, I have only had to go to this extreme only twice. I hate walls. They are a pain in the butt to clean up and often the object will break when you do so. Only use this when nothing else will work.
Rafts & Brims
In Lesson 3 I covered Brims. Again, think of this as the brim of a hat. Rafts and Brims are similar. Both are tricks you can use to expand the object to print bed surface area. The more surface area, the better adhesion to the bed and the more success you will have. There are distinct differences however.
A brim will expand the surface area outward (it radiates outward) around the part(s) of the object that sits flat on the bed. If you want to simply create a surface area that for the entire area of the object, you want to use a Raft. If you have many small surface areas, a Raft is a better choice. For example, if you decided that you want to print the horse standing up on its four legs, a raft would be a good choice. When in doubt, go with a raft.
Adhesion Factors (Bed Leveling, Temperature/Humidity, Orientation, Filament Failure)
The most important thing to get right with a print is adhesion to the bed. An object that is being printed needs to adhere well to the bed. If not, it can warp or worse, move/fall off the bed. Either would be a failure and you would need to restart. Failures typically occur because of one of three things. I added a couple more that are more rare. As with all of these tips, trial end error will help you figure out what works.
1. Bed Leveling: First and foremost, your print bed needs to be level to print something properly. Every printer has a different process. Newer ones have auto-leveling. I highly recommend spending the extra dollars on a printer with that feature. Either way, check your printer manual on how to properly level the bed.
2. Temperature and/or Humidity: Both the print head and the print bed heat up. The print head heats up to melt the plastic. The print bed heats up to hold the plastic down as the object prints. The temperature you want to set the bed to depends on a number of factors. The primary factor is the type of plastic. When you do your slicing, the software will automatically set the print head and print bed temperature parameters according to the type of plastic selected. These are preset by the manufacturer and generally are universally agreed. However, sometimes you need to change the temperature. The most common reason for needing to change it is relative humidity. The ideal conditions for a good print with PLA is somewhere around 30 to 40% humidity. Too much (above 50%) is not good and too little is not good. In the summer, printing in the basement (with my dehumidifier running) is easy. However, fellow New Englanders know, and my dry hands can attest, that the air gets very dry in the winter. Increasing the heat of the bed and print head along with enclosing the print makes up for that lower humidity.
3. Orientation: Another reason a print can go wrong is because an object is just poorly oriented on the bed. Always take extra care when you are in the slicing software to make sure the flat side of the object is on the bed flat. Most software will have a “put it on the bed” type of option. This makes it easy.
4. Filament Failure: This is rare, but does happen. If you have filament that has sat around for a bit in a very dry or very humid (either end of the spectrum) it can become brittle. Filament usually comes with a silica packet to absorb excess moisture. I have found that if I keep it in the plastic packaging with that silica and in the box, it lasts a very long time. Store it carefully is all I am saying.
5. Nozzle Failure: All kinds of other failures can occur, but luckily they are rare. One of the less rare is if the print head comes loose. Sometimes that leads to plastic flooding the head, leading to the need to replace it. Luckily print heads (also known as nozzles) are pretty inexpensive. I bought a small bag of about 10 for something like $20. Good to have extras on-hand.
Cleanup
This part of the lesson will be very short. If you printed with any type of scaffold and/or a brim or raft, you will need to clean it up. As modelers, I know you are all in-tune to this process. The sheet of plastic parts that come with model airplanes and cars remind me of the same process. Craft snipers/scissors and/or knives are your friend here. Some people also use a little bit of fine sandpaper. Once cleaned up, they are ready to paint.
Other Photos
Here are some other pictures I took along the way for this lesson.
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