3D printed metal, strength and suitable uses?

I’ve ordered new catches to secure the upper doors on our horse trailer.  I bought aftermarket ones as it said they had better tolerances (the OE ones are quite rattly) and now they’ve arrived I suspect they are 3D printed, possibly aluminium, 3mm thick.

They only hold the upper doors which are fairly light, but you normally travel with them open so they face forward into the airflow so do get buffeted a bit by the wind.

So can anyone tell if these are some sort of 3D printed or additive style construction, and if so, would you expect them to be brittle or be prone to abrading when shaken around a bit?

They 3D print space rockets now so if it’s been made properly it will probably be up to the job 🙂

It wouldn’t be cost effective to 3d print them.
I reckon waterjet/laser cut than a really course media blast or ceramic tumble.

Yes I agree 3d printing wouldn’t be my first choice as they are perfectly flat!

As above. Why do you think they’re 3d printed? Looks like they could be very easily made from cutting out from sheet/plate, and much cheaper.

<p style=”text-align: left;”>They look quite rough but with square edges, having had another look I reckon they might be powder coated.  Just a bit strange, I’ve not seen metal look like this before and they are going to slide up and down inside a plastic housing.</p>
The reviews from other buyers are positive so presumably they will work fine!

For the life of me I can’t think what process would make edges that rough but also cut the profile. At a push I’d from the photo they are pre zinc coated steel which has been water jet cut. But then they would way much more than alu.

Photo with flash. They are quite sparkly (doesn’t show so well on camera).

They feel a bit light for steel.  The photo on the listing looks shinier and the cut out sections look bigger

https://www.ebay.co.uk/itm/144575741677?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=eumu8nuet-i&sssrc=4429486&ssuid=dYL7NmZpSua&var=&widget_ver=artemis&media=COPY

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They look waterjet or laser cut then sandblasted to get an even finish.

That’s been profiled out of sheet then blasted.

Looking at their other items for sale they have similar sheet metal brackets etc with bends and either disc’d or blasted finish. Typical fabricator strategy to hide surface blemishes on sheet stock.

Edit – you wouldn’t be able to 3d print those, pay postage and make money for £12.95

Laser or water jet cut from sheet then bead blasted, if they ‘feel light’ they’re probably Aluminium…

So it’s been pointed out that these are not printed parts for the horse box as there are cheaper better ways to do it.  The question about printed part strength was also mentioned.   The answer to that is it depends on the process & control measures used to produce the part.   I often design parts for Ti6-4 DLMS process (laser sintering) and the manufacturer suggests stressing the parts assuming 1000MPa UTS based on coupon testing so similar to billet.  There is some evidence that fatigue performance is not as good as billet.    I would use higher FoS for a printed part but not sure this lack of trust in the properties of printed parts is fully justified, but there is just more experience/evidence of the billet properties.  Many parts can be printed but typically it is only beneficial to print when the part is complex…   in my opinion…

Water jet cut face finish gets worse with faster feed rate. Faster feed rate = less time on the cutter = cheaper.

Have you put a magnet on them to see if they are steel or aluminium?

If they are steel, does one face look a crisper cut and one side more ragged? If so they could have been hi-def plasma cut (I get my dropouts done by that and there is definitely a good and bad face to them).

I vote laser cut plate, then bead blasted.

If you look at the cut edge it’s jagged and has a decent burr in places. That happens because ally is very reflective at the specific laser wavelength typically used – usually around 600nm. Only 10% or so of the laser energy is absorbed into the melt pool, the rest bounces around the pool causing an unstable cut and that rough edge. Typically occurs when cutting thicker material.

Waterjet could’ve made a neater part. Or using a shorter wavelength laser, such as a blue 400nm unit (but they’re rare and expensive).

None of the above is really relevant in this instance – I just wanted to add to the nerding.

Aluminium powder is €70/kg.  Not a chance they’re 3D printed.

There’s also no layerwise surface marks on all sides which would give you the build direction.  The marks on the interior and exterior edges are cutting marks from what looks like a water jet cutter at a slight angle to normal.

Oh, and to answer the title of the thread.  3D printed metal, made using a laser melting system will have properties that’re equal to wrought equivalents in strength and bending in their as-built condition.  The only place they’ll differ is in fatigue as the poor surface quality of 3D printed parts is a crack initiator.  If you subsequently machine the top 250-500microns from stress hot spots in the design, the fatigue will also be equivalent.

in certain cases, using in-situ tailoring of the beam profile, it is possible to get 3D printed materials which approach forgings in terms of strength.

All of these require a controlled processing environment with controlled powder feedstock.  If you feed it rubbish and don’t control it properly, performance will rapidly drop through either poor recoating, poor melting or oxygenation of the material.

I’ve worked directly with titanium 64, TiCp, various grades of steel, aluminium and other more exotics such as vanadium, tungsten and platinum.  The principles hold true for all.

Thanks for all the nerding, interesting reading 🙂 Forgot to do the magnet test which I was going to do when I first opened the package, I did weigh one at 31g so when they are swapped I’ll weigh the old one 🙂

Yeah, I suspect not printed.

I’m currently running an aluminium printed rear linkage on my old Scott Spark – mostly as an experiment in modding the geometry of a 2012 frame to something a little more modern XC, raising the rear travel to 120mm, 120mm forks and slackened the head angle by 1.5deg with an angleset which brings it surprisingly close in terms of geometry to a 2020 Spark.

In it’s raw printed for it’s very pale – and for reference, printed in china it was about £125 inc shipping.

Not got a close up picture of it fitted – but plastic prototype as below. Added the ability to adjust BB height and travel but run in in the middle (120mm and matching sagged BB height to stock bike) as feels about right.

In terms of strength/weight I went fairly conservative – roughly doubling the high stress areas wall thicknesses of the stock item and adding ribbing too. I did some basic FEA assuming a bottom out from a 1.2m drop and sat on the saddle with 100psi in the rear shock (worse case I deemed possible, higher rear shock pressure lowered the peak load) and I should be ok. Also most failure cases have the rear wheel contact the seattube with in effect locks the rear wheel so hopefully not to unsafe in a failure case.

It’s been on the bike for about 9 months now and done a BPW trip and a trip to Scotland without fail so far. I did have to manually fettle the bearing seats as got them printed undersized and have slightly oversized one that tends to creak a fair bit so intend on fitting a spare I had made sometime soon.

That’s really good, always like to see experimentation like this backed up by calculations!.    I am impressed at relatively low cost of the part…    How much material was added to allow for post machining to ensure you got the bearing fit to account for part distortion during the build?

Yeah, was a bit of a design exercise for the sake of it – but worked out better than expected. Cost was due to shopping around Alibaba for about 2 weeks (I set myself a limit of £150 for this).

Added about 1.5mm on the bearing faces and used a Dremel to fettle the faces to size but in hindsight should have bought an adjustable reamer as would have been able to get a better finish on the faces and better tolerances as at least one is too loose.

One issue I did have was there was some warping of the part – about 0.5mm between sides if you know what I mean – but a blowtorch and some gentle manipulations sorted that. Not ideal but was better than scrapping he part!