Author Topic: 3D Printed Quorn Tool & Cutter Grinder  (Read 33064 times)

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #25 on: December 19, 2015, 03:16:28 PM »
I am just having a mess about with the CAD file now.  The bed on this machine is 150mm square so I can almost squeeze it in at 45 degree across the bed.  However I am looking at making this part in two pieces as I want the printed layers in two planes to maximise the material strength.  I think the vertical column part of the casting will have a section tee'd into the main casting to pick up one of the bars.  I can then plastic weld these parts together.  Otherwise my option is to split the casting between the bars and insert an alloy plate that has been bored to tie the bars and bridge the printed parts, this could also be applied to the other printed casting for the other end.   I am still doodling those ideas.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Fergus OMore

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #26 on: December 19, 2015, 03:39:48 PM »

What will become a problem is that you will have to hang a 1/6th HP 6000rpm motor, its pulley and a casting to hold that and a spindle and abrasive wheel --at the end of  a 1.250" column and hold it from a casting. In my case it was cast iron whilst your is- plastic. This is why I offered the loan or whatever you my rusty old wreck to see what happens.

In my opinion, the relative  weight that plastic has to endure   is mind boggling.

Offline awemawson

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #27 on: December 19, 2015, 03:45:09 PM »
Does anyone have the approx weight of a built Quorn.  Ours isn't going to weigh that much, but its not a bad idea to design it for that weight and some.   Looking at the base bar supports now and thinking they need to be fully supported along the bottom of the casting/print rather than just a foot.

Looking back through my records, the last Quorn that I sold, which was fully equipped, with all collets, spare wheels etc and in a fitted case had a packed weight of 40kGs.. This was a particularly nice one that I had bought from a deceased estate but had been left in a shed to rust by the family for far too long before they sold it.
Andrew Mawson
East Sussex

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #28 on: December 19, 2015, 04:01:05 PM »
This is what I propose to do with the printed casting.  I have done parts like this in the past and then welded the edges.  The column part will be printed as is, the bar support printed on its side to make best use of the printed parts strength.



As for motor, I am not expecting to use the standard motor, maybe a brushless outrunner as I don't expect to grind the same amount as a full cast iron based Quorn and thank you for a guide on weight.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Pete49

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #29 on: December 19, 2015, 08:27:53 PM »
wow you are getting on with it. Loving it.
oops..........oh no.........blast now I need to redo it

Offline Fergus OMore

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #30 on: December 20, 2015, 03:21:11 AM »

As I have said earlier, it is line boring the two 1" diameter bed bars- one fixed and one to advance and retard- in thous- and not twist and bind that are - interesting.

My first efforts in this direction were gimcrack and hopelessly wrong. Oh, and the cast iron bores closed up on splitting.

I'm getting addicted to learn what happens


Good Luck

Norman

Offline RotarySMP

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #31 on: December 20, 2015, 04:20:34 AM »
I like the way you interlock the two components. One of my friends has been 3D printing for a few years, and it is really cool the completely differnet solutions to mechanical problems he comes up with, compared to a subtractive worker (Machinist).

Look forward to seeing how this pans out. You can still lost PLA cast the parts if they turn out to lack rigidity.

Sounds like most Quorns get made as a skills challenge, and end up barely or unused. At least a plastic one won't rust :)

Mark


Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #32 on: December 20, 2015, 04:42:04 AM »
 LOL.  I think you got it spot on Mark, this is as much a challenge and as such the design will morph as problems arise.  Take for instance the vertical part of the casting.  To make that more rigid rather than add ribbing to the vertical column I would be better moving the fixing round 90 degrees then mirror it, so instead of one bolt it has two fixing bolts.   I am going to try acrylic rod in 25 and 30mm for the bars.   The 30mm should allow me to machine in the spiral with some yet to be devise cunning geared gadget.  So there goes the idea of not having plastic on plastic bearings.

No worries on this one closing up Norman, it will be printed with the slit or some yet to be thought of bar clamping method.   I expect to get none of this right first time and now for some delay whilst I prepare further modelled parts.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Fergus OMore

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #33 on: December 20, 2015, 05:34:39 AM »


Sounds like most Quorns get made as a skills challenge, and end up barely or unused. At least a plastic one won't rust :)

Mark

Certainly it becomes a test of just how good or bad that your machining skills have reached. As the end product? Well, are a lot of easier set ups to grind tools and I have never got to making 1/10th inch slot drills which was Chaddock's intention.

I'm fascinated to see whether  the proposed construction method is feasible when  very different materials are used.

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #34 on: December 20, 2015, 06:01:33 AM »
You already know Norman, my biggest challenge will be when I start building the parts away from the bars and things start to flex.  That is where my main concerns are, and if I can devise alterations to stiffen those parts without them becoming unwieldily.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline awemawson

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #35 on: December 20, 2015, 06:44:06 AM »
Prof. Chaddock made it as step on the way to his BRM model. See page 31 of this link:

http://www.sm-ee.co.uk/wp-content/uploads/2014/12/2010-05.pdf
Andrew Mawson
East Sussex

Offline Fergus OMore

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #36 on: December 20, 2015, 06:50:13 AM »
Of course you could build it like- err uhm- Tower Bridge?  Not with hundred of tons of lead but a steel framing.

As for the spiral, the trick is to use a drill attachment with an end mill rather than a lathe tool which takes a - Quorn to sharpen it.

Enter the little men in white coats and carrying a straight jacket. Couldn't resist it- sorry!

Comes from living in the grounds of a Victorian  Mental Institution! Not far to carry my suit case- as and when.

Norman


Offline Arbalist

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #37 on: December 20, 2015, 07:24:53 AM »
Joules, are you going to make the plastic parts the same size as the cast iron ones would be or are you going to make them larger wherever possible? I see no advantage to copy the CI parts verbatim unless you want the finished product to look identical?

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #38 on: December 20, 2015, 07:35:59 AM »
Cheers guys, your input is very welcome.  Arbalist I am treating the casting like a listed monument, alterations and extensions will be in keeping with the sytle of building.  No I am heavily modifying the parts to make best use of my 3D printing knowledge and experience.   The devil is truly in the detail, at present I have no idea how long just preparing the CAD models will take.  You can't just tap plastic and expect fasteners to behave as though in metal, so in places inserts and buttons must be incorporated into the print, but nothing too complex.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #39 on: December 20, 2015, 07:57:35 AM »


This is the altered casting parts.  I moved the fixing points and doubled them to make the column more rigid, this also impacted on the blending of the two parts, so I had to alter that.  I am also missing some of the chamfering I will add for the weld fillets.  The original CAD model I got is pretty awful for 3D printing as it isn't watertight and has many overlapping and twisted surfaces, so I am pretty much having to redraw each part from scratch for 3D print ready parts.  What I learn here will be applied to other jobs and projects so none of it is a waste of time.

So far the wall thickness is around 7mm, which for PLA has huge strength if you print in the 40-50% infill range.  The vertical column will also be drilled and tapped in the base, so allowing it to be bolted to the mounting board/plate.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline mattinker

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #40 on: December 20, 2015, 08:49:53 AM »
Joules,

what are you planning to mount your plastic Quorn on? A piece of granite counter top and bolts compressing the plastic could help enormously with rigidity!

Regards, Matthew

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #41 on: December 20, 2015, 09:01:01 AM »
Matt, bolting is going to be a contentious issue as PLA will creep if put under too much stress for too long  (lesson learned from printed violin)  So it maybe something like cycle quick release system so its only firmly clamped during use.   Experimentation will be fun  :scratch:

Another option is to sleeve the bolts so creep can be limited then skim the sleeves if needed later on.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Fergus OMore

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #42 on: December 20, 2015, 09:22:40 AM »
Nice granite plates are on offer at Aldi. Just bought one!

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #43 on: December 20, 2015, 11:46:17 AM »
Haaaaa, been a long time since I had a print failure, well, I just had one   :(



I am so thankful it was only 1hr into this 24hr print.  Serves me right for being cocky and trying to print both parts at the same time.   The larger part was right on the edge of the bed and must have got cooled faster than the rest, so it started to curl.   It's not a total loss, I was a bit BELT & BRACES in my print settings.  I went a bit heavy on the wall thickness, again this could have contributed to the curl as it gets really thin where it started to lift.  I had printed a skirt to hold it down, but it seems to have pulled away from that.   Maybe printing on a raft would be better, but the surface finish suffers.

On to the next one, new settings to be determined from close inspection of these parts.  I am printing in 0.15mm layers, 50mm/s print speed and at 210℃ and 45% infill, think that last one can be dropped to 40%  That will also help speed up the next print, and I shall do each part separately.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Fergus OMore

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #44 on: December 20, 2015, 12:35:03 PM »
Ah well, but at the end of the day- you have grit. 

And the answer to  the obvious question- neither have I.

Norman

Offline nrml

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #45 on: December 20, 2015, 12:59:51 PM »
You could use epoxy resin to bond the plastic parts to the base. There will be little stress on the plastic and the bonding should be plenty strong enough. You can incorporate a few holes in the design of the printed parts for dowel pins for added joint strength. 

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #46 on: December 20, 2015, 01:22:00 PM »
Cheers nrml, epoxy just doesn't bond to the clean surface of PLA, now printing the parts with dowel holes is a pretty good idea.  Will look into doing that on a later revision of this first print.  The print is progressing now so see what we end up with tomorrow.

6mm dowel holes now included in base of casting for registration on mounting board (most likely a sheet of aluminium)
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #47 on: December 21, 2015, 05:12:07 AM »
Half way there.... On the first casting   :coffee:



Not so happy with the infill, but this print is VERY rigid.  Next part due off the printer in 10hrs.

If it all goes to plan, this should be the internal structure (infill) I will use in all the future prints.



Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline Joules

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #48 on: December 21, 2015, 03:59:12 PM »
A good 10hrs later, second part of the first casting done.  Quick clean up, pulling off the support material and push them together for a trial fit.



This is the fit with no clean up.  Needle file will knock off some of the small blobs on the mating surfaces.



I won't know how accurate my centres are till I can put some bars in.   Theory has it any error should be the same in the next part printed, so hope the centres are equal, next print will confirm that.  I picked up my Perspex rod today and the 30mm is a very snug fit in the vertical column.  I'm a gnats under on the 25mm, if the hole is elliptical, "Norman" it will get a skim if thats the case.

 

Last one for now showing the quality of fit and the holes for the dowel pins, they probably will be fitted with epoxy, but more to grout them in than glue.  I'm a lot happier in the print quality on this second part.  Once this section gets the bars in and welded, I can skim the underside to get them true.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline John Rudd

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Re: 3D Printed Quorn Tool & Cutter Grinder
« Reply #49 on: December 21, 2015, 05:00:41 PM »
Have to say, I'm very impressed with the quality of the 'printed' items....  :dremel:

I'm also more impressed at your ability in mastering this technology.... :bow: :bow: patience at learning a new skill such as this is not one of my strong points...  :(
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