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How to Make a Silicone Mold Out of a 3D Printed Piece

If you have a 3D printer and want to create multiple copies of an object, or if you want to cast your 3D printed piece in a different material, you might want to make a silicone mold out of it. Silicone molds are flexible, durable and easy to use.

What You Will Need:

  • A 3D printed piece that you want to make a mold of
  • Silicone rubber (you can use either tin-cure or platinum-cure silicone, depending on your preference and budget)
  • A mixing container and a stirring stick
  • A mold box (you can use any container that is slightly larger than your 3D printed piece, such as a plastic cup or a cardboard box)
  • Mold release agent (such as petroleum jelly or spray-on mold release)
  • A knife or scissors

Step 1: Prepare Your 3D Printed Piece

Before you make a mold of your 3D printed piece, you need to make sure that it is clean and smooth. You can use sandpaper, files or other tools to remove any rough edges or imperfections. You can also paint or prime your 3D printed piece if you want to improve its appearance or durability. However, make sure that the paint or primer is completely dry before proceeding to the next step.

Step 2: Apply Mold Release Agent

To prevent the silicone from sticking to your 3D printed piece, you need to apply a thin layer of mold release agent over the entire surface. You can use petroleum jelly, spray-on mold release or any other product that is compatible with silicone. Make sure that you cover every detail and crevice of your 3D printed piece. You can use a brush or a cotton swab to spread the mold release agent evenly.

Step 3: Place Your 3D Printed Piece in the Mold Box

Next, you need to place your 3D printed piece in the center of the mold box. The mold box should be slightly larger than your 3D printed piece, leaving some space around it for the silicone to fill. You can use any container that is sturdy and leak-proof, such as a plastic cup or a cardboard box. You can also use hot glue or tape to secure your 3D printed piece to the bottom of the mold box.

Step 4: Mix and Pour the Silicone Rubber

Now, you need to mix and pour the silicone rubber according to the manufacturer’s instructions. You can use either tin-cure or platinum-cure silicone, depending on your preference and budget. Tin-cure silicone is cheaper and easier to work with, but it has a shorter shelf life and may shrink slightly over time. Platinum-cure silicone is more expensive and sensitive to contamination, but it has a longer shelf life and does not shrink.

To mix the silicone rubber, you need to measure the correct ratio of part A and part B (usually 1:1 or 10:1) and pour them into a mixing container. Then, use a stirring stick to mix them thoroughly until they are well blended and have no streaks. Be careful not to introduce any air bubbles into the mixture.

To pour the silicone rubber, you need to slowly and carefully pour it over your 3D printed piece in the mold box. Start from one corner and move across the surface in a thin stream. Make sure that you cover every detail and crevice of your 3D printed piece. You can also tap or shake the mold box gently to help release any air bubbles trapped in the silicone.

Step 5: Let the Silicone Cure

After pouring the silicone rubber, you need to let it cure for the recommended time (usually between 6 and 24 hours) at room temperature. Do not disturb or move the mold box during this time. You can also place the mold box in an oven at a low temperature (around 60°C) to speed up the curing process.

Step 6: Remove Your Silicone Mold

Once the silicone is fully cured, you can remove your silicone mold from the mold box. Carefully peel off the silicone from the sides of the mold box and gently pull it out. You should be able to see your 3D printed piece embedded in the silicone. Then, use a knife or scissors to cut along the edge of your 3D printed piece and remove it from the silicone. You should now have a perfect replica of your 3D printed piece in silicone.

Congratulations! You have just made a silicone mold out of a 3D printed piece. You can now use this mold to cast

One of the challenges of 3D printing small, thin parts is heat dissipation. Heat dissipation is the process of transferring heat from the printed part to the surrounding environment. If the heat dissipation is not efficient, the part may warp, crack, or melt during or after printing.

There are several factors that affect heat dissipation in 3D printing, such as:

  • The material of the part and the print bed. Different materials have different thermal conductivity and specific heat capacity, which determine how fast they can transfer and store heat. For example, metals have high thermal conductivity and low specific heat capacity, which means they can quickly dissipate heat but also heat up quickly. Plastics have low thermal conductivity and high specific heat capacity, which means they can retain heat for longer but also take longer to cool down.
  • The geometry and size of the part. Smaller and thinner parts have less surface area and volume to dissipate heat than larger and thicker parts. This means they can overheat more easily and deform under thermal stress. Additionally, complex geometries with sharp corners, overhangs, or thin walls may create hot spots or weak points in the part that are more prone to warping or cracking.
  • The printing parameters and environment. The printing speed, temperature, layer height, infill density, cooling fan speed, and ambient temperature all affect the heat dissipation of the part. Generally, higher printing speed and temperature, lower layer height and infill density, higher cooling fan speed, and lower ambient temperature can improve heat dissipation and reduce warping. However, these parameters also depend on the material and geometry of the part and may need to be adjusted accordingly.

To improve heat dissipation in 3D printing small, thin parts, some possible solutions are:

  • Choose a suitable material for the part and the print bed. For example, use a material with high thermal conductivity and low specific heat capacity for the part, such as metal or carbon fiber composite. Use a material with low thermal conductivity and high specific heat capacity for the print bed, such as glass or ceramic. This way, the part can quickly dissipate heat to the print bed and the print bed can slowly release heat to the environment.
  • Optimize the geometry and size of the part. For example, increase the surface area and volume of the part by adding fins, holes, or channels to enhance heat transfer. Reduce the complexity of the geometry by smoothing sharp corners, eliminating overhangs, or increasing wall thickness to avoid hot spots or weak points.
  • Print a “sacrificial” part right next to your print. This has the same effect as increasing the surface area of the part and will give the part time to cool.
  • Adjust the printing parameters and environment. For example, lower the printing speed and temperature, increase the layer height and infill density, decrease the cooling fan speed, or raise the ambient temperature to reduce thermal stress on the part. However, these adjustments may also affect the print quality and strength of the part and should be done with caution.

Heat dissipation is an important aspect of 3D printing small, thin parts that should not be overlooked. By understanding the factors that affect heat dissipation and applying some solutions to improve it, you can achieve better results with your 3D prints.

Coasting and wipe distance are two settings that can affect the quality of your 3D prints.

Coasting is a setting that tells the printer to stop extruding filament a little bit before the end of a perimeter or an infill line. This helps to reduce the pressure in the nozzle and prevent oozing or stringing. Coasting can also reduce the amount of blobs or zits that appear on the surface of the print. However, coasting can also cause gaps or under-extrusion in some cases, especially if the coasting distance is too large or if the filament is not viscous enough.

Wipe distance is a setting that tells the printer to move the nozzle along the perimeter or the infill line after it stops extruding filament. This helps to smooth out the end of the extrusion and reduce any excess filament that may ooze out of the nozzle. Wipe distance can also improve the surface quality of the print by hiding any imperfections or seams. However, wipe distance can also cause over-extrusion or dragging in some cases, especially if the wipe distance is too large or if the nozzle temperature is too high.

Both coasting and wipe distance are useful settings that can help you achieve better 3D prints. However, they are not mutually exclusive and they may interact with each other in different ways depending on your printer, filament, and model. Therefore, it is important to experiment with different values and find the optimal balance for your specific situation. You can use a test model like this one (https://www.thingiverse.com/thing:1363023) to see how coasting and wipe distance affect your prints and adjust them accordingly.

Level first, then mesh, then Z offset. Or do I set the Z offset first, then level then mesh? Or is it…

I always start with mechanical functions, then move to software compensation. No sense in trying to set a Z offset on a bed that’s tilted 20 degrees. Where would the offset even apply to? The highest point? The lowest point? I’m not sure.

First, set your mechanical level. This is done by turning the screws and making sure that your bed is mechanically aligned to your nozzle. Next, set your mesh to compensate for any variance in the bed flatness. I don’t use Z offset, I haven’t had to. But if you do, this is the point that you should implement it. The machine has a sense of where the bed is so it is able to apply an accurate Z offset.

Sometimes prints will have issues only at a specific height. The symptoms may be poor fill at a specific height, layer shift that always occurs at a certain Z, or something else that seems to consistently occur at a certain height.

When this happens, I start looking at, and around, the lead screws for Z. I look at the motors, the screws themselves, and the bearings. When I inspect the lead screws, I make sure there are no physical issues, such as nicks or dings in the screw itself and that the lead screw isn’t bent in that location.

I had a mishap over the weekend that made me have to stop my print. The print was too long and I had too much into it to want to start over, so I decided to print the other piece and glue them together.

As I was doing it, I noticed how well the pieces fit together. I’ve done this in the past and the parts didn’t fit together well. I’ve spent a lot of time tuning my printer and making sure that it is printing to the proper sizes.

I realized that one of the benefits of this effort is that, when things do go wrong, I am able to put the pieces together because the sizes match.

This post wrote itself over the weekend. I was printing a bracket for my wife. Estimated print time was about 32 hours. Before I went to bed on Saturday, I checked the amount of filament and realized that I needed to change spools in order to be able to finish the print.

M600 to the rescue. So far so good. Simple task, just press M600, let the nozzle get out of the way. Take out the old filament, put the new filament in, press resume. Good to go then I can go to bed.

When I did so, I pressed the button for one of the macros that I created, “Extrude new filament through Bowden tube.” As soon as I did, the machine started to home itself. Now I’m in trouble. You see, because of the size of the bracket that my wife needs, I had to use up pretty much the entire bed. What this means is that when the machine homes it would come down on top of the already printed material. I had to e-stop the machine. Now what? Well, I measured the height of my print. Dropped that much material through the table in Cura, then printed the rest of the print. When I glued them together I ended up with a tiny seam. But a little bit of primer over the seam made it disappear.

Then I removed the homing sequence from my macro.

I’ve seen a number of people asking for functionality related to controlling or monitoring their printer remotely. The easiest way is to set up a Raspberry Pi and attach it to your printer. With the price of Raspberry Pi’s right now, though, this is a significant cost. I’ve had good luck with Armbian on a Le Potato that costs substantially less. After some experimentation, I ended up replacing the firmware on my printer with Klipper and putting Klipper on my Le Potato. It’s been working great.

If the sides of a calibration cube are a little bowed, there are a couple of things that I would look at.

  • e-steps/rotation distance (Klipper): if your extruder is extruding too much material, the material has to go somewhere.
  • calibrate Z: same thing as above, if your z steps are off, you might not be moving up as much as you think you are. The extruder is calibrated to extrude a certain amount of material. If you end up extruding more material, it needs to go somewhere
  • pressure advance: your nozzle may be oozing a little bit and causing your sides to become bowed