FDM

43 Articles

Sheet Metal Forming With 3D Printed Dies

January 9, 2025 by 16 Comments

Sheet metal is very easy to form, including the pressing in of intricate shapes with dies and a hydraulic press, but the dies themselves are slightly harder to come by. What if we could 3D print custom dies to stamp logos and more into sheet metal? This is the premise of a recent video by the Stick Shift Garage channel on YouTube in which dies are printed in PLA+ (solid infill) and used to stamp 1 and 2 mm thick sheet metal with the channel’s logo.

As can be observed in the video, the results aren’t bad at all after a couple of tweaks and adjustments to the pressure, but of course there is room for improvement. Some helpful commentators suggest improving the dies with properly rounded edges on the die’s shape and paying attention to K-factors and kin so as not to overstress or tear the sheet metal. In terms of die longevity, the PLA+ dies began to wear out after about a dozen tries but not the point of failure. Here other filament types might work even better, maybe even to the point of competing with a CNCed metal die.

Considering that this was a first attempt without a lot of pre-existing knowledge it went pretty well, and a future video was promised in which improvements will be shown off.

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New Tullomer Filament Claims To Beat PEEK

December 8, 2024 by 37 Comments

Recently a company called Z-Polymers introduced its new Tullomer FDM filament that comes with a lofty bullet list of purported properties that should give materials like steel, aluminium, and various polymers a run for their money. Even better is that it is compatible with far lower specification FDM printers than e.g. PEEK. Intrigued, the folks over at All3DP figured that they should get some hands-on information on this filament and what’s it like to print with in one of the officially sanctioned Bambu Lab printers: these being the X1C & X1CE with manufacturer-provided profiles.

The world of engineering-grade FDM filaments has existed for decades, with for example PEEK (polyether ether ketone) having been around since the early 1980s, but these require much higher temperatures for the extruder (360+℃) and chamber (~90℃) than Tullomer, which is much closer (300℃, 50℃) to a typical high-performance filament like ABS, while also omitting the typical post-process annealing of PEEK. This assumes that Tullomer can match those claimed specifications, of course.

One of the current users of Tullomer is Erdos Miller, an engineering firm with a focus on the gas and oil industry. They’re using it for printing parts (calibration tooling) that used to be printed in filaments like carbon fiber-reinforced nylon (CF-PA) or PEEK, but they’re now looking at using Tullomer for replacing CF-PA and machined PEEK parts elsewhere too.

It’s still early days for this new polymer, of course, and we don’t have a lot of information beyond the rather sparse datasheet, but if you already have a capable printer, a single 1 kg spool of Tullomer is a mere $500, which is often much less or about the same as PEEK spools, without the requirement for a rather beefy industrial-strength FDM printer.

Excerpt from 1995 Stratasys patent, showing the drawings of FDM layers, including brick layers.

Brick Layers: The Promise Of Stronger 3D Prints And Why We Cannot Have Nice Things

November 9, 2024 by 84 Comments

It is a fact of life that 3D printed parts from an FDM (fused deposition modeling) printer have weaknesses where the layers join. Some of this is due to voids and imperfect layer bonding, but you can — as [Geek Detour] shows us — work around some of this. In particular, it is possible to borrow techniques from brick laying to create a pattern of alternating blocks. You can check out the video below.

The idea of ‘brick layers’ with FDM prints was brought to the forefront earlier this year by [Stefan] of CNC Kitchen. Seven months after that video you still can’t find the option for these layers in any popular slicers. Why? Because of a 2020 patent filed for this technique by a 3D printing company which offers this feature in its own slicer. But is this patent even valid?

It’s no surprise that prior art already exists in the form of a 1995 Stratasys patent. The above image shows an excerpt from the 1995 Stratasys patent, covering the drawings of FDM layers, including brick layers. This covered all such ways of printing, but the patent expired in 2016. In 2019, a PrusaSlicer ticket was opened, requesting this feature. So what happened? A second patent filed in 2020 assigned to Addman Intermediate Holdings: US11331848B2.

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What Actually Causes Warping In 3D Prints?

October 14, 2024 by 35 Comments

The 3D printing process is cool, but it’s also really annoying at times. Specifically, when you want to get a part printed, and no matter how you orientate things, what adhesion aids you use or what slicer settings you tweak, it just won’t print right. [David Malawey] has been thinking a little about the problem of the edges of wide prints tending to curl upwards, and we believe they may be on to something.

Obviously, we’re talking about the lowest common denominator of 3D printing, FDM, here. Other 3D printing technologies have their gotchas. Anyway, when printing a wide object, edge curling or warping is a known annoyance. Many people will just try it and hope for the best. When a print’s extreme ends start peeling away from the heat bed, causing the print to collide with the head, they often get ripped off the bed and unceremoniously ejected onto the carpet. Our first thought will be, “Oh, bed adhesion again”, followed by checking the usual suspects: bed temperature, cleanliness and surface preparation. Next, we might add a brim or some sacrificial ‘bunny ears’ to keep those pesky edges nailed down. Sometimes this works, but sometimes not. It can be frustrating. [David] explains in the YouTube short how the contraction of each layer of materials is compounded by its length, and these stresses accumulate as the print layers build. A simple demonstration shows how a stack of stressed sections will want to curl at the ends and roll up inwards.

This mechanism would certainly go some way to explain the way these long prints behave and why our mitigation attempts are sometimes in vain. The long and short of it is to fix the issue at the design stage, to minimize those contraction forces, and reduce the likelihood of edge curling.

Does this sound familiar? We thought we remembered this, too, from years ago. Anyway, the demonstration was good and highlighted the issue well.

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Reinforcing Plastic Polymers With Cellulose And Other Natural Fibers

September 9, 2024 by 10 Comments

While plastics are very useful on their own, they can be much stronger when reinforced and mixed with a range of fibers. Not surprisingly, this includes the thermoplastic polymers which are commonly used with FDM 3D printing, such as polylactic acid (PLA) and polyamide (PA, also known as nylon). Although the most well-known fibers used for this purpose are probably glass fiber (GF) and carbon fiber (CF), these come with a range of issues, including their high abrasiveness when printing and potential carcinogenic properties in the case of carbon fiber.

So what other reinforcing fiber options are there? As it turns out, cellulose is one of these, along with basalt. The former has received a lot of attention currently, as the addition of cellulose and similar elements to thermopolymers such as PLA can create so-called biocomposites that create plastics without the brittleness of PLA, while also being made fully out of plant-based materials.

Regardless of the chosen composite, the goal is to enhance the properties of the base polymer matrix with the reinforcement material. Is cellulose the best material here?

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FDM Filament Troubles: Keeping Hygroscopic Materials From Degrading

July 17, 2024 by 18 Comments

Despite the reputation of polymers used with FDM 3D printing like nylon, ABS, and PLA as being generally indestructible, they do come with a whole range of moisture-related issues that can affect both the printing process as well as the final result. While the concept of ‘baking’ such 3D printing filaments prior to printing to remove absorbed moisture is well-established and with many commercial solutions available, the exact extent to which these different polymers are affected, and what these changes look like on a molecular level are generally less well-known.

Another question with such hygroscopic materials is whether the same issues of embrittlement, swelling, and long-term damage inflicted by moisture exposure that affects filaments prior to printing affects these materials post-printing, and how this affects the lifespan of FDM-printed items. In a 2022 paper by Adedotun D. Banjo and colleagues much of what we know today is summarized in addition to an examination of the molecular effects of moisture exposure on polylactic acid (PLA) and nylon 6.

The scientific literature on FDM filaments makes clear that beyond the glossy marketing there is a wonderful world of materials science to explore, one which can teach us a lot about how to get good FDM prints and how durable they will be long-term.

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DIY Spacer Increases FDM Flow Rate For Faster, Better Printing

July 12, 2024 by 8 Comments

The host of problems to deal with when you’re feeling the need for FDM speed are many and varied, but high on the list is figuring out how to melt filament fast enough to accommodate high flow rates. Plus, the filament must be melted completely; a melty outside and a crunchy inside might be good for snacks, but not for 3D printing. Luckily, budget-minded hobbyists can build a drop-in booster to increase volumetric flow using only basic tools and materials.

[aamott]’s booster, which started life as a copper screw, is designed to replace the standard spacer in an extruder, with a bore that narrows as the filament gets closer to the nozzle to ensure that the core of the filament melts completely. Rather than a lathe, [aamott]’s main tool is a drill press, which he used to drill a 0.7 mm bore through the screw using a PCB drill bit. The hole was reamed out with a 10° CNC engraving bit, generating the required taper. After cutting off the head of the screw and cleaning up the faces, he cut radial slots into the body of the booster by threading the blade of a jeweler’s saw into the bore. The result was a bore wide enough to accept the filament on one end, narrowing to a (roughly) cross-shaped profile at the other.

Stacked up with a couple of knock-off Bondtech CHT nozzles, the effect of the booster was impressive — a 50% increase in flow rate. It’s not bad for a prototype made with simple tools, and it looks a little easier to build than [Stefan]’s take on the same idea.

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