Member postings for lee webster

Hmmm, a piece of wood for £21.08. Sounds good!

I didn't like synchronous mode when I first tried Solid Edge. But now I've heard it described in that way I realise that it's very close to the way Designspark works. I think in other systems it might be called direct modelling. Now that I have used Dspark for so long I might actually get along with synchronous mode in Solid Edge!

Fantastic! I can't even imagine how to start such a project.

I managed to park near Smiths in Camborne and buy the magazine. I am not dissapointed! When After I had carried out a tempory repair to my shed/garage roof I wondered which way to replace the felt next year. New felt, fibreglass or some sort of metal roof. I hadn't considered the rubber method even though I was aware it existed. Now I can add that system to my list. The rest of the magazine is very readable too. I especially liked the page with private ads.

Thanks IanT and Nigel, I will check out the link later. I have two 3D printed sprues to sand smooth!

Lee

Your enthusiasm in persevering with Solid Edge gave me the incentive to try it again. It isn't an easy programme to get to grips with, especially after using a simple CAD programme like Designspark. But after about 15 minutes I had drawn half a model engine conrod, added draft to relevent edges and fillets to others. I then went a step further and hollowed it out, a resin 3D print can consume a lot of resin. There are parts of the programme I find awkward, but that is more likely to be me. I exported an STL of the conrod and it loaded fine in my slicer software.

Is the link for the text files in this posting? I might start spending more time with the programme.

A bit of a setback today. I had glued the conrod to the base and filled any small gaps yesterday. This morning I sanded the filler and sprayed the part with primer. This afternoon I was going to sand the primer when I noticed that the conrod had somehow become distorted.

This is the gap on one side.

But the other side is almost perfect.

I manage to get the conrod off the baseplate without breaking it. And straightened it out with a bit of gentle heat from a hair dryer.

I have now produced two files for printing. One on the Ender3 of the conrod and base as one unit, no join, at 0.12 layer height. A five and a half hour print.

The other file is the same but for the resin printer. A two and a half hour print with five times as many layers.

This picture is of one of the test prints I did on the resin printer. The file came from a company called Amerilabs. I have included a five pence piece for scale. There are windows in the skyscrapers, I can barely see them let alone measure them!

With any luck I will have both prints to work on later tomorrow.

Dave.

My CAD computer is only used for CAD and the slicing software for 3D prints. So it is as stand alone as I can make it. It is only a small laptop with a solid state drive, but with no anti-virus and internet shenanigans to slow it down, it is fast. Boot-up, 10 seconds. Solidedge, 5 seconds. Designspark, 8 seconds. On my old plodding internet computer Designspark takes over 60 seconds to load, Solidedge would take 2 to 3 minutes. I could do with better graphics on it, it only has the built in graphics which aren't up to much.

This morning I felt like going for a walk. I decided to go to Tesco, about three miles away. I stopped at the village shop on the way to buy a bar of chocolate and got to Tesco about an hour later. I bought two packs of sandpaper type nail files for sanding my 3D prints. I left Tesco and walked to Morrisons, it was on the route home, to do some shopping. As I left Morrisons I had an idea of a way to improve a small engine I am designing. I had no way of making a sketch so it would have to wait untill I got home. I think walking is good for thinking.

I got indoors at about midday. Most of the walk had been dry with a small amount of Cornish "mizzle" to cool me down. The alteration to my engine looks a lot better than the previous design which I had alread sliced ready to 3D print.

When I had Solidedge installed on my CAD computer the system date was not "up to date" as it were because of another CAD programme I was using, Designspark, that wanted to log on to its home site each month. My CAD computer isn't connected to the internet and I didn't want Designspark to get upset, so I keep the system date at the same date I installed Designspark. Maybe by doing that I was confusing Solidedge into thinking it hadn't been installed long enough to tell me to upgrade. Designspark does give a message each time I run it that there is no internet connection. Solidedge never did. I wish I had tried the date thing with SolidWorks, I might still be using it!

JasonB.

Your thinking is along the same lines as mine. It will be a fairly easy job to print out the gates as you picture. I might try and incorporate a pouring basin, or just pour as is. Thanks for the input.

Dave.

Thanks for the support, it's appreciated! As you might have guessed, I am making it up as I go along. I have had some very nice greensand castings from PLA prints from my Ender3, but the time taken to get them to a good enough finish for casting seemed longer than the design and print combined.

I am still learning about the correct settings for resin prints. For example, the exposure time for the general layers, not the bottom layers which need more time, is very critical. I downloaded two test pieces and printed them out. The detail is stunning. Text 1.5mm in height by a hairs thickness extruded from the surface is sharp and clear. I printed the first test print at 2 seconds exposure. Examining the details and reading the internet instructions I then set the printer at 2.5 seconds and did a second print. The improvement was very clear. I reset the printer to 2.1 seconds and printed the conrod. I think I will reset it to 2.4 seconds and try again. Getting orientation of the piece right is also important, and all these things take time. I am getting there slowly! With a layer thickness of 0.05mm ( I believe the printer can go down to 0.035mm) an extra .4 of a second adds up when there are several hundred, or more, layers to print.

I have filled and sanded the base and glued the conrod to it. The glue join will need a bit of fettling before I can spray it with primer and make the surround for the casting sand.

David,

I recently bought a resin 3D printer thinking it would help me produce better castings. I haven't tried a casting yet, but resin prints are not the solution I thought they would be. I still have an idea lurking in my head that the prints could serve as part of a casting process. I will get a bit more experience before trying it.

I think this voice is a computer reading a text file. Annoying, but it gets the job done. When I tried to learn Solid Edge I found the youtube videos by a doctor or maybe professor Seif very good.

John, Virtually all modern computers enable you to have more than one window open at once. You could have a Solidedge tutorial open in youtube, pause it and switch to Solidedge running in another window to draw what you have just watched, and then switch back to the tutorial. There is normally a bar acroos the bottom of the screen, on windows it is called the task bar, this bar shows you what programmes are running.

I must admit that Solidedge had too many features I didn't need to make it of any use to me. But oddly, SolidWorks didn't seem to make me feel the same. Perhaps it's because I was using the student version which is a cut down version of the full programme. I would rather use SolidWorks, it's just too expensive.

Thanks David!

I only printed one half of the rod because I thought I could then take two moulds from it, they should match perfectly, and then glue the two halves together for pouring. Your way sounds better.I will check my part for draft, I gave it two degrees on all sides. I could increase that to say three or four just to be on the safe side.

Your patterns look as though they are resin printed. Did you print them at an angle or directly on the build plate?

I still haven't got my printer sorted yet, still trying different settings so I don't mind doing another print.

Lee

All good information. I hadn't thought about fumes from the epoxy when molten metal hits it. I know it's been used by others in the casting process. I think it's safe to use sodium silicate in the same situation. Maybe that's the best way to go.

I spent some time recently repairing my garage roof. It is a timber garage the length of two cars. I re-felted the roof several years ago, and it needs doing again. My repairs will last until next year. I really must get the issue with the shed roof article.

PatJ, I have been calling it resin bound sand. What I mean is fine sand mixed with epoxy resin. I know it has been used as a core mould, I will try it as a mould for the pattern. The sodium silicate is the other method I will try.

All the points you raised have been added to my list! Thanks.

Lee

Hi JasonB,

I have only made one pattern. My idea being that I would produce two halves of the mould from the one pattern and bond them together. I have seen it done on another thread, the McDonald tractor. That's why I decided to use a bound sand rather than a rammed sand. And because I made the conrod pattern in resin, it is nowhere near as strong as the PLA print from a printer like the Ender3 and would probably be destroyed with ramming. I had toyed with the idea of feeding at the big end and have a feeder/riser at the small end. I also wonder if I should try to incorporate a pouring basin.

I am hoping that because I have placed the conrod in the exact middle of the base the two halves of the mould should line up. I hope!

Edited By lee webster on 21/08/2022 16:29:13

I have 3D printed a conrod pattern with my resin printer and a baseplate to fix it to with my Ender3. I will have to fill the layer lines in the plate then I can glue the conrod to it. I will make a frame to go around the plate high enough to make a sand mould. Either resin bound sand or sodium silicate, not sure which so I should try both. I used the Ender3 to make the base as I am unsure about printing a large flat surface on the resin printer. The base has two raised bosses to locate the conrod which is partially hollow on the back. The conrod is 89mm long with a 6mm dia hole in the little end and big end. An earlier attempt at making a pattern this way is also shown. I still have to figure out how to get the molten metal, aluminium, into the mould. The conrod will be visible on the engine I am hoping to make. The big end is elongated by 3mm to allow the casting to be cut.

I was once invited to watch a pour of cast iron at an engineers a couple of years ago. He added glass, bits of broken bottles, to his crucible. He was advised to do it by a foundryman. Apparently the molten glass acts like a magnet to attract a lot of the dross. He used brake rotors, disc brakes, for his scrap. They must have been from a lorry or railway train by the looks of them.