Thanks: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 91 to 105 of 133
Thread: The Journey for a Master Square
-
6th March 2013, 07:09 AM #91Philomath in training
- Join Date
- Oct 2011
- Location
- Adelaide
- Age
- 59
- Posts
- 3,149
A foam pattern will work with CI. Essentially, the hot metal burns out the foam as it goes. The beauty of a foam pattern is that you don't have to worry about draft on the pattern as you would with a solid pattern. The other thing is that they can be rammed into the sand more easily rather than having to mess around with doing cope and drag sides sequentially. (This casting has some depth so may have to be done more carefully).
For stress in castings there are two things to remember.
- Thick sections cool more slowly than thin sections
- Internals cool more slowly than external features
- Metal contracts after it cools
Quickly looking at Josh's renderings I would expect the spokes to solidify first, followed by the sides. As the sides are constrained by the sand, the spokes will be trying to pull the sides inwards. Last to cool will be the main box corners. The outsides will cool first followed by the insides of the corners. This will tend to pull the corners back and want to make them more acute. While not as experienced as a pattern maker in these things I suspect that the resulting casting will probably have 4 concave sides but by how much I would not want to guess. Depending on the ratio of spoke thickness to the main body, there may or may not be problems. Looking at the renderings I would think that they could be thicker and/or the main walls thinner but not having done much casting I could be wrong, especially if the casting shop is a good one. I would be concerned about gating as the sprues could well cool off before the rest of the casting, giving rise to voids. If thicker the spokes may be a better place to introduce metal to the (Most of my "casting design" has been for injection moulding - if this was a plastic part I would be slapping the designer around the head as I support designing parts that cause least problems in manufacture. However, Josh is bigger than me so I'll pass on that option)
Michael
-
6th March 2013 07:09 AM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Age
- 2010
- Posts
- Many
-
6th March 2013, 08:14 AM #92
I was almost going to mention something similar earlier Pete. I don't know anything about casting stresses, but all the square frame levels i have looked at are made like that, a circle inside the square. There must be a reason....
1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.
-
6th March 2013, 12:42 PM #93GOLD MEMBER
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 7,775
Hi Ewan,
Got a picture?
The ones I have seen are pretty much a square inside a square. Like this one,
Though I did like this one.
How about it Josh?
I would have thought that regardless of shape.... IF it survived cooling, stress reliving would take care of any other issues. Maybe stress reliving before it cools would help? Looking at an engine block I wonder how they could cast then, of course they could have a couple of goes at it. Surly the foundary would say "well thats never going to work" if they thought they were going to have issues?? But then I wouldnt really have a clue and maybe they assume you know what you are doing?? Fun stuff this casting game.
StuartLast edited by Stustoys; 6th March 2013 at 12:46 PM. Reason: change links to pics
-
6th March 2013, 12:54 PM #94Pink 10EE owner
- Join Date
- Aug 2008
- Location
- near Rockhampton
- Posts
- 4,304
May provide some ideas
Parallels on Busch Precision, Inc.Light red, the colour of choice for the discerning man.
-
6th March 2013, 12:55 PM #95SENIOR MEMBER
- Join Date
- Oct 2012
- Location
- Australia
- Posts
- 765
The main considerations for the design for me in order of priority are: minimal weight for less 2 micron deviation of geometry with 1000N side load, 200x200x200mm size, able to not just measure but also transfer geometry ie: clamping space, simple to mould, ease of machining geometry and thermal stability.
I did few other designs design studies one of which was a circle in a square but the weight was higher than the + design for the same rigidity same went for the X and simple filleted box and a pitch circle kind of thing. Actually X was pretty close to the performance of the + design but the distortion was not uniform it introduced a wave in the faces under load which I did not like. The main problem I had with the "circle in the square"(the weight was not much more around a kilo from memory) was that it provided no easy way to clamp. And when using it as a spotting master you need to be able to clamp it to the surface plate or the wringing will drive you insane. Also need to be able to clamp to it with when used on a surface grinder to transfer it geometry onto the part. There were a few others that were a of various ribbed designs but that would have required cores that I ended up discarding because I thought they would be too complicated and hence too costly to mould.
The purpose of the hub is face to face rigidity and maintains parallel, it is also a handy place to have a handle to manurer it around being about the centre of rotation; as I would hate to drop one :S
Allowance has been made in the pattern for some distortion and rate of cooling problems (the "spokes" are a little thicker than I would have liked), but it is a balance between the processes and intended function. I think I have the balance just about right, but the only way to be sure is to get it cast. Failure is always an option but it is hard to see how it will fail so badly that it will end up being a useless artefact. The heat treatment oven is computer controlled and is capable of controlled ramps and I'm confident that I can remove enough of the residual stresses in the casting.
I'll also point out Taft Peirce honed in on the a similar design concept for their box parallels, maybe this is why they charge $2000 for each one.
-Josh
-
6th March 2013, 01:12 PM #96
The ease of clamping with Josh's design is the thing I like, there are plenty of commercial examples of the same type of design.
Series 5100, 5200, 5300,5400, 5500, 5600 , 5800 parallels : box , cube , giant cube , planer/boring machine , 3 dimension, steel , manufactured by Busch Precision
The FEA Josh did, showed surface distortion under load with the diagonal bracing version, but less distortion in parallelism with the orthogonal bracing.
After arguing around for a day or so, the final version is pretty much what you see,
Regards
Ray
-
6th March 2013, 01:22 PM #97SENIOR MEMBER
- Join Date
- Oct 2012
- Location
- Australia
- Posts
- 765
Oooo. I Like that second one, who makes that?
I would also assume that the foundry has a pretty good idea of what they are doing, and leave it in the mould long enough before knocking it out to allowing it to cool slower. I also assume that if it did not survive the initial cooling they would be able to cast another one with modifications to the moulding by adding chills and/or changing the ramming pressure.
-Josh
-
6th March 2013, 01:27 PM #98SENIOR MEMBER
- Join Date
- Oct 2012
- Location
- Australia
- Posts
- 765
I really like their hugs and kisses parallel.
a1065.png
-
6th March 2013, 01:46 PM #99GOLD MEMBER
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 7,775
lol
So glad I took the links out. I had to go find it again lol. turns out its a company thats been linked before.
Machine Checking Square Frame - Machine Checking Frame and C.I. Testing Bed And Floor Plate Supplier & Manufacturer from Indore, India
Nervermind Ewan, while searching for the above link I came across a couple of circles. Thought the second one is a circle so you can move the level.
Stuart
-
6th March 2013, 01:54 PM #100SENIOR MEMBER
- Join Date
- Oct 2012
- Location
- Australia
- Posts
- 765
-
6th March 2013, 03:52 PM #101SENIOR MEMBER
- Join Date
- Oct 2012
- Location
- Australia
- Posts
- 765
The Pattern
Christian and I have been swapping different 3d files back and forth until we managed to hit a combination that worked. We split the pattern into halves and then quarters. Here are a couple of pictures he sent me today of a quarter being machined. If I understand Christian right the first picture one actually is an 8th as the end mill is not quite long enough to do the full depth.
small_0004.JPG
small_0005.JPG
small_0007.JPG
small_0008.JPG
Great finish straight off the cutter, it hardly needs to be sanded at all.
-Josh
-
6th March 2013, 04:35 PM #102GOLD MEMBER
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 7,775
-
6th March 2013, 04:53 PM #103Intermediate Member
- Join Date
- Jan 2012
- Location
- Melbourne
- Posts
- 44
That is looking great, gotta love CNC for patternmaking! To me the webs look chunky enough to not cause problems. Christian, I once left a little jelutong dust on the table... instant rust when the coolant hit it on the next job. Used Renshape ever since.
Neil
-
6th March 2013, 05:06 PM #104SENIOR MEMBER
- Join Date
- Oct 2012
- Location
- Australia
- Posts
- 765
what renshape do you use?
-
6th March 2013, 05:11 PM #105SENIOR MEMBER
- Join Date
- Oct 2012
- Location
- Australia
- Posts
- 765
Similar Threads
-
Installing vice: how square is square?
By tomnewby in forum WOODWORK - GENERALReplies: 12Last Post: 27th June 2009, 08:03 AM -
square to table or square to fence
By yjnb in forum BANDSAWSReplies: 1Last Post: 20th July 2008, 07:50 AM -
The Journey Of Man
By Barry Hicks in forum WOODIES JOKESReplies: 2Last Post: 24th April 2008, 04:50 PM -
I'm going on a journey, man
By journeyman Mick in forum MOTOR HOMES, CARAVANS & CAMPINGReplies: 34Last Post: 3rd July 2007, 11:54 PM -
The journey
By ozwinner in forum WOODWORK - GENERALReplies: 7Last Post: 12th July 2004, 05:23 PM