MemberSeptember 30, 2019 at 11:58 am
I have a bit of an interesting project I am trying to do, essentially I want to 3D print the belt pegs for my Stero dishwasher. They currently cost around $3.50 a piece and they go through about 100 or so a month, if not more.
I could print them for probably half or less of the price and also modify them to be stronger so they break less.
Any of you guys have any experience on things like this? I’ve 3D printed a couple of things and plan on getting my own machine but I’m hoping to find someone who has gone through a similar process.
AdministratorSeptember 30, 2019 at 12:24 pm
It all comes down to the type of machine and type of plastic used. A cheap FDM machine using PLA will print something that will probably fail in a year. A mid-grade printer using brand name ABS should be able to make a part that’ll last for years.
Sadly, if there is one thing I’ve learned from my own 3D printer, it is that it never prints as fast or as affordable as you wanted 🙂
MemberSeptember 30, 2019 at 1:22 pm
I believe it.
My plan is to get the Monoprice Ultimate 3D Printer II, using PETG and I’ve printed a sample in ABS with someone else’s and it comes out nice, I just plan on making it indestructible.
It’ll still be cheaper than $3.50 a piece I hope. If I can keep the part under 100 grams then it’ll be cheaper, I’m looking at about 40 grams including supports and that’s with the part modified for extra strength.
MemberSeptember 30, 2019 at 2:18 pm
So the problem with 3D printing any parts is knowing if the plastic has 2 very basic requirements:
1. Is it food safe. Will it be OK if a customer ingests those pieces of plastic? If the answer is no, you leave yourself open to all sorts of liability issues.
2. Will it put up with the temp? Most ware-washers will start at 140 degrees F and go past 180F. Most 3D plastic will soften at those temps.
MemberSeptember 30, 2019 at 2:22 pm
That is a good point and one that I have considered. PETG is considered food safe and depending on how the final product comes out, it’s either food grade or not.
PETG has a heat deflection temp of approximately 65*C – 80*C depending on who you ask.
I would think considering that the machine is designed to bring objects to 160*F +, the peg will have to resist at least 160*F but I don’t think it’ll get much hotter than that, the PEG itself is plastic so it’s conduction is going to be low and it will be exposed to those higher end temps only for a short period of time and then end up back in room temperature for a little and then back through.
Once the object hits the heat deflection temp it then becomes flexible but I think it would take some effort for the entire part to hit that temperature.
But I won’t know till I try it.
AdministratorSeptember 30, 2019 at 2:36 pm
A great article listing 3D filament with food grade approvals is here: https://3dfilaprint.com/filament_overview/food_safe_filaments_print.htm
Of course, the whole “approved” vs “cleared” debate is really complex, and too often, a company will make claims about their products they can’t back up.
BTW; what a fantastic topic! There is very little information out there about 3D printed food grade parts, so I’m sure this thread will be a great resource.
MemberSeptember 30, 2019 at 2:53 pm
Awesome, good information on there, there’s definetley a lot of options, just a question of which ones will work best on what printer, seems like some of them require a specific kind of printer with more than a heated bed and all metal hot end.
Yeah, it’s amazing how little information there is, seems like occasionally and end user will post something about it somewhere but there’s really not a lot of info.
When I do get the printer in with the PETG I’m sure I’ll find many, many reasons to use it and I’ll be able to do a lot of perfecting and testing.
MemberSeptember 30, 2019 at 6:44 pm
Olivero, we have eight Hobart flight machines. Our labor efforts to keep up with replacing broken flights is ridiculous.
Once you settle upon what type of plastic to use, I suggest installing just a limited number in a location that you can easily track them down so you can closely monitor their durability over the long haul. I recommend that before making any huge investment in the additional materials and time to make/install a bunch of them.
Those flight have a rough life – not only in temps approaching 200° and harsh chemicals, but also by the abuse they incur by the stewarding folks cramming dish wares into them for 12-18 hours or more a day.
MemberOctober 1, 2019 at 9:01 am
I know, it’s ridiculous how many of them break, the main thing will be making sure that the PETG can survive the temps, that’s really my main concern as I can keep modifying the design of the Peg to make it stronger but if the plastic won’t survive the temps then it just won’t work at which point I’ll have to find another material.
I want a 3D printer regardless as I’m sure it’ll come in handy for all the little things that break where replacing the whole thing is the only way to fix that little part.
MemberOctober 1, 2019 at 11:47 am
The selection of a plastic material is quite complicated. It involves not only food service and temperature, but also environment and chemicals that it will be exposed to as well as the big de grader, UV. Consult with the makers chemist to get the best one for your application. It’s a ever changing industry with new compounds coming out often. The US Navy has now gone to having a printer on board all ships to cut down on parts inventory. But those level of printers are problably out of our price range.
MemberOctober 1, 2019 at 11:50 am
Very true, it will be a bit of a challenge indeed and I just hope it works out in the end, everything looks like it will but I am at the near tipping point for PETG’s tolerance so I think only time will tell at this point.
I figured ships eventually would just considering how useful it can be and the need to be versatile in fixing problems.
AdministratorOctober 4, 2019 at 7:08 am
While on the topic of 3D printed parts, has anyone here ever used a laser cutter to produce small parts? Of course, not one of those million dollar Trumpf machines, but the new generation of $400 cheap Chinese tube laser machines. They’ll easily work with many plastics, but to cut metal you’d need something much, much beefier.
I have a small home laser, and it is remarkably reliable for small plastic parts that can be cut from sheets of plastic. Very fast, and it just looks plain cool to see the laser at work.
MemberOctober 4, 2019 at 11:51 am
I’ve never used one but one of my co-workers has a CNC machine to cut circuit boards.
MemberOctober 4, 2019 at 12:18 pm
Never worked with a laser system, but several water jet machines and a couple of plasma cutters.
AdministratorOctober 8, 2019 at 12:09 pm
Waterjet systems always fascinate me – it is incredible to watch water (and a little bit of grit) slice through metal like a slice of bread.
MemberOctober 8, 2019 at 9:00 am
Okay, for some feedback.
We got the PETG in and printed a Peg, it help up to the temperature just fine so far, only ran it through a couple of times but it looks no worse for wear.
Only problem is figuring out how to make it snap on the belt without breaking the part that holds it in place on the rail.
MemberOctober 8, 2019 at 12:21 pm
Do you have a way of measuring the Durometor rating of the original and yours?
MemberOctober 8, 2019 at 12:26 pm
No, unfortunately not.
MemberOctober 8, 2019 at 12:36 pm
Any local engineering colleges or plastic manufacturers? They’ll have one.
MemberOctober 9, 2019 at 7:58 am
It’s part of the elasticity to be able to snap over the bars. Opening the gap up a millimeter might make for them to fall off when hot. I’m sure that the expansion of the plastic from heat has to be a factor as well in the original design and material spec.
MemberOctober 9, 2019 at 11:45 am
Yeah, you are probably right, We’ll see. Once my printer comes in on Friday I’ll be able to test a lot more, especially in how the infill pattern is done to allow more flex.
MemberOctober 15, 2019 at 9:40 am
Alrighty, time for an update.
My printer has been running pretty much non stop since I got it and I’ve gone through so, SO many versions of this PEG and it seems like I’m getting places.
Hands down, the material is ridiculously strong, I mean it’s absolutely crazy, I don’t think anything short of a hammer and a vice would snap the head off it, so that’s good.
Running into some issues getting it to snap on properly, been playing around with a lot of different concept, it can definetley flex, it’s just a matter of finding a balance between too much flex and not enough as well as strength overall.
It’s starting to go in the direction of needing channel lock pliers to snap on the peg and for some reason, one end of it always breaks but the other end does not, so I’m working it out but it seems it might work out in the end.
AdministratorOctober 15, 2019 at 10:01 am
Curious what you are using to design the part? Was it an easy process to replicate the original part into a 3D model? Did you have to make any changes to the part to help it print successfully? Thanks so much for all the updates, this is very interesting!
MemberOctober 15, 2019 at 11:19 am
Have you measured with a vernier the inside diameter of each side. Is the lower side a bit smaller from droop? Sometimes precise areas are made with extra material to be machined off later for precision.
What really concerns me is that it may be to strong and if something gets caught wrong instead of breaking it may damage the flight rods, chain or drive.
MemberOctober 15, 2019 at 11:34 am
I’m using Sketchup PRO right now, I was using Blender but never got into 3D printing with it. I learned to 3D model in sketchup originally for space renderings and such so I just kind of stuck with that. I’ve made a few changes to make it stronger where the original always fails, at the base of the peg that rises upwards, hopefully this will make them last longer.
Yes, I measure the original ones and that’ s what I started out with, an exact replica of the original and then altered it from there.
It’s a valid concern you are voicing, I hadn’t really given too much thought to it, the original pegs are darn near impossible to get off and when brand new, they come with 2 pieces that go across the bottom to prevent it from coming out, so if I can get my version to be as difficult as theirs, that’s kind of what I’m going for.
MemberOctober 15, 2019 at 11:41 am
Yes, but are you measuring yours after build and cooling. I’ve seen were the weight in the build as it gets taller makes the bottom mushroom a small bit. To the point that a commercial machine has vortex coolers to dissipate the heat quicker from the build.
MemberOctober 15, 2019 at 12:47 pm
Yes, once it’s cold and been sitting for a while.
It doesen’t seem to shrink much, might be off by 0.002 MM or so.
MemberOctober 16, 2019 at 3:25 pm
I have successfully printed parts to repair an microwave interlock. I have found that annealing the finished product gave it quite a boost in strength. PLA anneals nicely with minimal shrinkage, haven’t tried PETG yet as I am still dialing it in. As far as I know part of the “food safe” issue is due to the micro fractures as part of the FDM process giving places for bacteria to hide and not get cleaned out easy, like a heavily scored cutting board.
MemberOctober 16, 2019 at 7:11 pm
Very true, the main concern is those “grooves” from the seams where the layers are made, but considering it;s a dishwasher, I’m doubting it’ll matter too much but we’ll see what ends up happening.
Happy to know others are using it in this industry as well for the same reason I am, we’ll definetley find a good use for ours even if the pegs don’t work out in the end.
MemberOctober 17, 2019 at 10:21 am
Just wondering as to what position you are printing the object?
MemberOctober 21, 2019 at 10:40 am
Well, after a lot of testing and prototyping. PETG does not hold up in the temperature. It simply warps when in the heat so it won’t work.
Now we’ll test Nylon.
AdministratorOctober 22, 2019 at 3:01 pm
Thanks for keeping us updated, despite your setback, it is very interesting to read your experiences.
MemberOctober 22, 2019 at 3:04 pm
Yeah, I’m sure someone will benefit one day.
Nylon is WAAAAAY flexible, it’s crazy. So it doesen’t work that well either, it holds up to the temp just fine but it gets really flexible when it gets wet.
MemberOctober 22, 2019 at 4:16 pm
Is there a tempering process that can be appied to printed parts?
MemberOctober 23, 2019 at 9:12 am
I believe so, not sure if it works on Nylon though,
I believe there is for other plastics.
AdministratorOctober 23, 2019 at 9:34 am
If you have an oven with an accurate thermostat, you can harden many printer materials on a pizza stone. Problem is, you usually need to be accurate to +/- 5 degrees….
MemberOctober 23, 2019 at 9:38 am
Interesting. What would I gain from it, make it harder to break?
AdministratorOctober 23, 2019 at 10:03 am
Definitely. Essentially you are melting the slices together, turning it into a more solid part. Your biggest issue will be shrinkage, so you may need to make a part, heat it, then take measurements to adjust the design.
MemberOctober 23, 2019 at 1:15 pm
Interesting, good to know.
MemberOctober 23, 2019 at 4:45 pm
Annealing is the keyword for this rabbit hole.
With PLA I was seeing about 2-4% dimensional shrinkage with a increase of tensile strength in the realm of 35%. I was clamping the part to a table and using a force gauge with a maximum function to find the shear strength.
MemberOctober 24, 2019 at 10:35 am
Very interesting, I’ve heard it from a co-worker as well who has annealed some of his parts.
MemberNovember 8, 2019 at 10:37 am
Interesting that you ventilated the web. Hope it doesn’t get any forgien build up internally.
MemberNovember 8, 2019 at 10:45 am
So far no issues. Been about a week with the nylon ones so far.
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