7 Tips for Using the Form 1+

by | Apr 9, 2015 | 3D Printing | 0 comments

Use a lever to detach models from the Form 1+ build platform

When you print items on the Form 1+ using support material, which you likely do for the vast majority of prints, the PreForm software automatically generates support structures, including a kind of raft below the model. The raft is a slab of plastic out of which the thin support structures sprout. PreForm automatically places little lifting tabs around the periphery of the raft to give you a place to grab on to and lift the raft off the build platform.

Formlabs, in its documentation, recommends using the metal scraper included with the Form Finish Kit for prying the part off the build platform. I find that is doesn’t work terribly well though. The metal scraper, since it is just a flat sheet of metal, doesn’t give you any mechanical advantage. It can be quite difficult to wiggle and pry your way under the raft using the metal scraper. Plus, it is very difficult to avoid scratching the build platform with the metal scraper, this reduces the life of your build platform (which costs $99 to replace).

So, instead of using the metal scraper to pry your parts off the Form 1+ build platform, I find it is much better to use a lever. Specifically, I like to use the angled tweezers, which are also included with the Form 1+. Simply, and carefully, place the tip of the tweezers under one of the lifting tabs on the raft. Then, gently lever up the part. This way, the tweezers act as a lever, which gives you much better mechanical advantage. Furthermore, since you will not need to scrape along the build platform, this method reduces wear on the build platform.

For larger parts, you can use the tweezers and metal scraper in tandem. First lever up one side of the raft with the tweezers. Then carefully place the scraper under the part, and lever up to finish the job.

To further decrease the risk of damaging your build platform during part removal, take two 1-inch pieces of 2mm shrink tubing, slip it over the ends of your tweezers, leaving only the tips of the tweezers exposed, and then use a source of heat to shrink down the tubing. The goal here is to apply a nice rubber coating to the tweezers so there is no metal-on-metal contact to scratch the build platform, which is certainly an improvement over the metal scraper included with the Form Finish Kit.

Put shrink wrap on your tweezers to avoid metal-on-metal contact with the Form 1+ build platform.

Put shrink wrap on your tweezers to avoid metal-on-metal contact with the Form 1+ build platform.

Use the tweezers (tipped with shrink tubing) to lever parts off the build platform.

Use the tweezers (tipped with shrink tubing) to lever parts off the build platform.

Don’t Rinse your Parts in Water

This tip is a simple one.  After the Form 1+ finishes a print, the piece needs to be cleaned. The Form Finish Kit is used to get all of the excess resin off a model after it is done printing, and remove all the support structures. In order to remove the excess resin, printed parts are soaked in a isopropyl alcohol bath for about 15 to 20 minutes. Finally, the part needs to be placed under UV light (either from sunlight, certain kinds of room light, or a UV curing box of some kind).

After you take your 3D printed part out of the alcohol bath, don’t rinse it off with water. For some reason that I have yet to figure out, rinsing parts in water often times leaves a kind of white residue on the part. I find that is is better just to let the piece air dry after its alcohol bath. The alcohol is volatile and will evaporate off your part, especially considering you will be placing it under some kind of fairly intense light for curing. By the time your part is done curing, it will be nice and clean and dry.

In fact, this brings up another reason not to rinse your part in water. The alcohol will evaporate very quickly and leave your part nice and dry, whereas water takes much longer to evaporate.

 

Invest in a Loupe

The Form 1+ is capable of printing extremely fine details in parts. In fact, the Form 1+ is capable of printing such fine details that it can sometimes be difficult to see well enough with the naked eye to clean up the models after printing. It can be difficult, for example, to scrape out little flecks of plastic of remnants of support material from tiny little crevices in certain types of models, like artistic models. Take a look at the print below. It is absolutely tiny, I think it is a good example to just how great the Form 1+’s fine detail performance is. But, it was also very difficult to clean, for example, the tiny cracks between the toes, fingers, and around the face.

This benchmark print is so small, it is quite difficult to clean with the unaided eye.

This benchmark print is so small, it is quite difficult to clean with the unaided eye.

A loupe is a little magnifying device that you can use to give your eyesight a little boost when cleaning parts. It can be really useful for making sure you clean all the hard-to-reach areas.

Take a look at the model’s left arm. You can see there are a few little scraps of plastic. These little bit of plastic are absolutely tiny, about one tenth of a millimeter across. They are very difficult to see with the naked eye. So, while I was cleaning this part, I used a loupe to get a better view of the area so I could clean it up.

I was able to use a loupe to help me clean up difficult areas of the model.

I was able to use a loupe to help me clean up difficult areas of the model. Next I’m going to work on her right hand.

 

Print in Batches When Possible

On the the downsides to using the Form 1+ is that it is not the fastest 3D printer. This is partially down to the fact that the Form 1+ has exceptional print resolution, meaning that even smaller prints are made from many, many, many layers. But the limiting factor the Form 1+’s printing speed is not the speed with which it completes each layer. The Form 1+ is actually quite fast at building individual layers. The slowest part of the printing process is the “peeling” operation the Form 1+ does to separate each layer from the bottom of the resin tank.

Now, the Form 1+ will only do one peeling operation per layer of the part, no matter how large the layer size is. Therefore, if you have multiple parts to print, you can save time by printing them all at once, rather than one at a time because you will need to do fewer peeling operations overall.

Take for example the model below, which is a part I was prototyping for the Vee pentapod robot. The part, pictured on the left, takes about an hour to print individually. But a set of three, as in the picture on the right, only takes about 1 hour, 45 minutes to print. So right there, I’ve already saved myself over an hour.

Servo back servo design

This part takes about 1 hour to print individually.

But printing three of these parts at once takes only 1 hour, 45 minutes, a time savings of  over an hour.

But printing three of these parts at once takes only 1 hour, 45 minutes, a time savings of over an hour.

Build Yourself a Curing Box

You might have noticed that, after removing a print from the Form 1+ and washing it off in IPA, the model still feels a bit soft, even sticky. That is because parts printed on the Form 1+ require additional curing time for the material to solidify fully. You can cure parts by exposing them to ultraviolet light (of a wavelength around 400-405nm). The easiest way to cure parts is just to put them in direct sunlight for 30 minutes to an hour.

But what if you are doing your printing in the evening when the sun is not shining? What if it is cloudy or raining? Formlabs says its resin can cure under room lighting, but, in fact, most types of room lights emit very little UV. Most incandescent lights have a phosphor coating on the inside of the bulb which blocks UV. The same goes for long florescent tubes. LED lights emit virtually zero UV. Sometimes compact fluorescent bulbs can emit some UV due to cracks in the phosphor coating. In general though, room lighting doesn’t hold a candle (haha) to the amount of UV emitted by the sun. Think about it, can you get a sunburn from your room lighting? No.

So, if you are going to be doing some printing in the evening or in bad weather, which I think is fairly common if you do 3D printing as a hobby and work full time, it can be extremely useful to build a curing box.

There are many different designs online that you can find easily with a Google search.

Repeatability Can be a Problem

The accuracy and repeatability of the Form 1+ is fairly incredible. Even after using the Form 1+ for several months, I never cease to be amazed by the printer’s reliability. The Form 1+ can print out the same model a dozen times and every single part will be exactly the same.

However, this unimpeachable repeatability can be a blessing and a curse. When I was in the process of starting up my Hub on 3D Hubs, I was printing some example parts to show the difference between the 0.1mm and 0.025mm layer heights on the Form 1+. Specifically, I was printing the Sunbathing model, which I think does a good job illustrating the capabilities of the Form 1+.

On my first attempt at printing the model with a layer height of 0.025mm I encountered a printing defect though. The models’s face and left hand stuck to the resin tank and ruined the print. It is a bit gruesome. I figured that the print just failed due to some random error in the printing process, so I moved the model to a different part of the build platform and tried the print again.

I was disappointed, but also amazed, to find that, after a six-hour print time, the second print failed in exactly the same way as the first print. Fortunately I had the forethought to label the prints so I could tell which was the first and which was the second because the models are indistinguishable.

Sunbathing @ 0.025mm layer height attempt #1

Sunbathing @ 0.025mm layer height attempt #1

Sunbathing @ 0.025mm layer height attempt #2

Sunbathing @ 0.025mm layer height attempt #2

So the lesson here is that the Form 1+ really does not have random print defects like other 3D printers. If you have a botched print, do not simply try the print again because it will fail exactly the way it did the first time.

Instead, you should learn from the printing error and make changes to your print, like re-configuring support structures or reorienting the model, in order to avoid repeating the same error.

 

Sunbathing @ 0.025mm layer height print failures

Sunbathing @ 0.025mm layer height print failures

Maintenance, maintenance, maintenance

If there is one “secret” to getting the most out of your Form1+, it’s performing regular maintenance. The Form1+ is a great machine, but one of the drawbacks is that you will need to be diligent about maintenance in order to keep the printer working its best. There are basically two main systems you will need to perform regular maintenance on:  the resin tank, and the optical path.

First, it is important to clean your resin tank on a regular basis. With every print there is the possibility that small bits of semi-cured resin will end up floating around the resin tank. These tiny pieces of “jelly” can interfere with the laser beam and cause print defects. If too much jelly accumulates inside the resin tank, it can even interfere with the laser enough to cause print failures. Formlabs has a number of nice tutorials for performing maintenance on the Form1+, including one for sifting jelly out of the resin.

The second system you will need to maintain is the optical path. Inside the Form1+ there is a laser emitter, as you probably know. The laser beam bounces off four mirrors and then passes through the bottom of the resin tank before shining into the resin to form your object. The laser first bounces off the x-axis galvanometer, then the y-axis galvanometer, then the small mirror, the large mirror, and finally it passes though the PDMS layer on the bottom of the resin tank. You can really only clean the last two parts of the optical path, the large mirror and the bottom of the resin tank.

You may need to clean the bottom of the resin tank from time to time. The bottom of the resin tank can sometimes get contaminated with dust, smudges, fingerprints, or other debris that can again interfere with the laser. Formlabs recommends using a plastic cleaning product called Novus 1 to clean the bottom of the resin tank. Formlabs has a good tutorial for cleaning the resin tank as well.

You may also need to clean the large mirror occasionally. Over time, the large mirror can and will attract dust. This is actually a worse problem than I think many Form1+ owners realize. Dust on the large mirror can severely interfere with the path of the laser, causing bad print defects and outright print failures. For a while, I was having trouble with print defects on my Form1+ when I did not realize my large mirror was dusty. In the image on the left below, you can see large sheets of cured resin hanging off the part. This print defect is called “ragging” because it looks like rags hanging off the model. The image on the right shows how much better my print quality got after I gave the large mirror a good cleaning.

IMG_20150702_102822

Severe ragging on this prototype part caused by a dusty large mirror.

Print quality was much improved after cleaning the mirror.

Print quality was much improved after cleaning the mirror.

One problem with performing maintenance on the large mirror is that it can be tricky to know when it gets dusty. When you shine a light straight down into the printer onto the large mirror, the mirror will often look very clean, even when it is dusty. To reveal dust on the large mirror, it is critical to shine the light onto the large mirror at a shallow angle. Shining light onto the mirror at a low angle is the only way to reveal that it is dusty. To clean the large mirror, it is very important to only use products made to clean sensitive optical components. It is of particular importance that you use a lint-free cleaning product, otherwise you will just be depositing more dust as you try to clean. Formlabs recommends using PEC-PADS to clean the large mirror. Check out the Formlabs tutorial on cleaning the large mirror for more detail.

There is a chance that you will need to clean the other three mirrors at some point:  the two galvometer mirrors, and the rear mirror. If you think your rear three mirrors are in need of cleaning, you will need to consult Formlabs support about it. It is wise never to take apart your Form1+ without asking Formlabs support first, otherwise you could violate your warranty. Plus, if Formlabs gives you the green light to clean your rear three mirrors, they will supply you with comprehensive and easy-to-understand instructions to do so.