Im attaching my step by step process for machining the cylinder head of the ML Midge. Maybe Im too new but I really dont know how I could make it through the work without staying organized. Do these order of operations seem the best? Does anyone else have a write up like this for diesel engines for model airplanes?
Does anyone else write out your machining steps ahead of time? ML Midge Cylinder Head
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For some of my HSM articles I have included order of operations on the drawings:
I do this as I develop drawings and modify the operations if I find a better way when machining the part(s).
Also my notes for myself if I'm not making a drawing.
I do this as I develop drawings and modify the operations if I find a better way when machining the part(s).
Also my notes for myself if I'm not making a drawing.
When I'm done with plans (I work from a copy of course) the back of each page is filled with notes, and other things explaining to myself how I'm
going to make those parts. Some is steps, some is DRO spacings/placement. They aren't quite as step by step as your photo above, but why not if it keeps you organized. I've also sometimes made a parts list so I can see what progress I've made. Also, we all solve machining problems differently depending on experience and available tooling.
going to make those parts. Some is steps, some is DRO spacings/placement. They aren't quite as step by step as your photo above, but why not if it keeps you organized. I've also sometimes made a parts list so I can see what progress I've made. Also, we all solve machining problems differently depending on experience and available tooling.
I use to write out every machining step ahead of time, and I did the same with the foundry work.
These days I pretty much have it memorized generally, and so I do the same thing mentally.
For a complex piece that requires machining steps in an exact sequence, I will generally jot down the sequence beforehand, so that I don't skip a step and botch the part.
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These days I pretty much have it memorized generally, and so I do the same thing mentally.
For a complex piece that requires machining steps in an exact sequence, I will generally jot down the sequence beforehand, so that I don't skip a step and botch the part.
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I sketch out all my machining steps and correct them along the way if I find issues with my original thinking or find a better way. They all go into a big 3-ring binder for that project so I can refer to them later on a future project if I'm doing something similar. More importantly though if the part has to be scrapped, I have proven steps to get me back to where I was. - Terry
And in a similar vein, when I started learning 3D modeling, I would often have several failed attempts at a part. This still happens frequently on complex parts.
I started taking a screen capture after every command, and save those screen captures to create a paper trail for development of a part.
Seems like a lot of trouble, but this method really pays off if I have to go back and make changes, and try to figure out what happened if something goes wrong.
Or if I am creating a similar part for another engine, and can't remember the exact sequence of modeling steps, I can do a quick visual review of the previously modeled part.
And if someone wants to know how I modeled a particular part, and perhaps compare notes with how they modeled the same part, I can send the .jpg files and they can see exactly how I developed my part.
3D modeling is much like virtual machining, and helps me envision the machining steps required for a casting.
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Edit:
My first attempts at machining (I learned machining about 15 years ago; so rather late in life) were pretty comical.
I would machine a surface, rotate the part in the lathe 180 degrees, machine some other surfaces, put the part in the mill and drill some holes, and the find out that not one of those operations created parallel/concentric surfaces. I remember exclaiming very loudly when I tried to assemble the parts "What the flock is going on here ?".
Every good machinist knows the tricks for success, such as not removing the part from the chuck until you have machined as much as possible on it. And you can actually remove the chuck from the lathe with the part still in the chuck, and then use that assembly on the mill.
Or if you do remove the part from the lathe, you must be very careful to get it back exactly centered, and I did not know how to do this accurately with an indicator either.
I have quite a few nice looking machined parts hanging on the wall that are totally useless.
There is no other way to learn except dive in and try things; and take notes about what does and does not work.
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I started taking a screen capture after every command, and save those screen captures to create a paper trail for development of a part.
Seems like a lot of trouble, but this method really pays off if I have to go back and make changes, and try to figure out what happened if something goes wrong.
Or if I am creating a similar part for another engine, and can't remember the exact sequence of modeling steps, I can do a quick visual review of the previously modeled part.
And if someone wants to know how I modeled a particular part, and perhaps compare notes with how they modeled the same part, I can send the .jpg files and they can see exactly how I developed my part.
3D modeling is much like virtual machining, and helps me envision the machining steps required for a casting.
.
Edit:
My first attempts at machining (I learned machining about 15 years ago; so rather late in life) were pretty comical.
I would machine a surface, rotate the part in the lathe 180 degrees, machine some other surfaces, put the part in the mill and drill some holes, and the find out that not one of those operations created parallel/concentric surfaces. I remember exclaiming very loudly when I tried to assemble the parts "What the flock is going on here ?".
Every good machinist knows the tricks for success, such as not removing the part from the chuck until you have machined as much as possible on it. And you can actually remove the chuck from the lathe with the part still in the chuck, and then use that assembly on the mill.
Or if you do remove the part from the lathe, you must be very careful to get it back exactly centered, and I did not know how to do this accurately with an indicator either.
I have quite a few nice looking machined parts hanging on the wall that are totally useless.
There is no other way to learn except dive in and try things; and take notes about what does and does not work.
.
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I cant say I take notes on the solid modeling but I do recognize that sometimes you have to model a part at least 70% of the way to figure out how you should have started. Mostly solidworks but some fusion 360 too
Yes, very true.
For complex parts, I often get far into the model only to have things start either blowing up, or perhaps a step damages a previous step.
Like machining, I have started several complex parts in 3D, and finished them, only to toss the design and start all over again with a cleaner and more simple design.
Generally, the more I do of anything, the better I get at it.
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Edit: The reason that I sometimes discard 3D models and start fresh is that unlike machining, where it does not matter about rough cuts and such, but rather the final surface/dimensions is all that matters, a 3D model with a lot of cumbersome and inefficient steps is stuck with all that material imbedded in the model forever, and it can't easily be cleaned up; and sometimes can't be easily modified either.
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Since do almost all my own drawings on projects.
I do not think about. You do not design something that would hard to build.
Most of time just do work but I have doing the for 60 years.
Just do a ball-bearing bore (±0.000,1") There is a different of making one or two or a hundred and all has to be (±0.000,1")
Dave
Still pencil scale drawing, measurements (all) and process this end, so don't end up turning away a piece one is meant to hold the job by.
Even using drawings from others I tend to write my own measurements as mistakes can come up on drawings , and I rarely ever follow the plan to a tee.
Even using drawings from others I tend to write my own measurements as mistakes can come up on drawings , and I rarely ever follow the plan to a tee.
When designing a part in 3D cad, I try to approach it in the same way that it will be machined.
I start by modelling the billet, then add features in the same way that they will be machined, e.g. a main bore relative to an end face, concentric features, fixing holes and finally non critical external features such as cooling fins.
I will also dimension the drawing in the same way, so if a feature such as a counterbore needs to be dimensionally controlled relative to another feature, such as the centerline of a port, then that is how it will be dimensioned on the drawing.
I start by modelling the billet, then add features in the same way that they will be machined, e.g. a main bore relative to an end face, concentric features, fixing holes and finally non critical external features such as cooling fins.
I will also dimension the drawing in the same way, so if a feature such as a counterbore needs to be dimensionally controlled relative to another feature, such as the centerline of a port, then that is how it will be dimensioned on the drawing.
I normally work from my own designs, even when working from plans I normally redraw them - this gives me the mental process of how I'm going to machine them and in what order.
With complex parts, I will normally do a sequence of machining stage drawings - like block up, main holes etc. etc. that way each stage drawing is relatively uncluttered with dimensions and whatever dimensions are there are for that stage of the operation.
Particularly with respect to how you are going to hold it for each operation.
Not as much work as it sounds and a lot less than rectifying mistakes or wrecked parts.
Regards, Ken I
With complex parts, I will normally do a sequence of machining stage drawings - like block up, main holes etc. etc. that way each stage drawing is relatively uncluttered with dimensions and whatever dimensions are there are for that stage of the operation.
Particularly with respect to how you are going to hold it for each operation.
Not as much work as it sounds and a lot less than rectifying mistakes or wrecked parts.
Regards, Ken I
I normally do design-build and always try to design for simplicity of build. I make drawings ahead of time because it saves so much machine time. The drawings are constantly updated to "as-builts". I also keep a composition book/notebook for each project.
Normally when machining, I often try to choose a flat surface as the "standard" for machining . From that surface I can machine, measure, ... other flat surfaces when I machine..
And as Ken said:
That's really important
Of course there are many different ways to process it, but having a way to hold it for further processing will save a lot of effort and time.
And as Ken said:
That's really important
Of course there are many different ways to process it, but having a way to hold it for further processing will save a lot of effort and time.
Simple jobs, generally no. With a complicated part yes.
Castings often need considerable care in finding a finished part inside them, sometimes involving compromises. After a careful survey, I may take initial light cuts just sufficient to create datum surfaces. These allow measurements to be refined, sometimes requiring corrections to the initial datums.
Castings often need considerable care in finding a finished part inside them, sometimes involving compromises. After a careful survey, I may take initial light cuts just sufficient to create datum surfaces. These allow measurements to be refined, sometimes requiring corrections to the initial datums.
BobsModels
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Here is what I used to make a part (4 of them) which is part of the valve assembly for a Bates & Edmonds 25HP model I have been working on. In addition to the arc sides, and a shaft hole it needed two tapped holes at 90 degree angle to secure it to the shaft, a 2-56 and a 0-80, see photo. The setup involved movements in the Bridgeport X-Y axis, a large rotary table, a small x-y table on the large rotary table, an adjustable angle plate on the small x-y table, a small rotary table on the angle plate, and a small 4 jaw chuck attached to the angle plate, see photo. The next picture is the set of instructions that gets the part to rough rectangle with all the holes, there is another drawing that finishes all the arcs.
Whenever I make a complex part I always lay out instructions. I often make sure that when producing the part in 3D (Alibre) that I make sure to have instances of partial completion for use in machining. Last picture shows several other parts made using the same method. Typically when a part is completed on the mill, the chuck is removed and mounted on a lathe for parting off.
Bob
Whenever I make a complex part I always lay out instructions. I often make sure that when producing the part in 3D (Alibre) that I make sure to have instances of partial completion for use in machining. Last picture shows several other parts made using the same method. Typically when a part is completed on the mill, the chuck is removed and mounted on a lathe for parting off.
Bob
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peterl95124
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I hate it when plans come with descriptions of, or ordered lists of, operations to be performed, I always DO have a list of operations and critical dimensions with me any time I go out the the milling machine, but the process of making my own list is part of the process of understanding the part to be made. I also usually have used a "sharpie" to mark out the bar stock as well, just to double and triple check where the operations are to be performed and that they really do look correct.
A related topic is whether plans should have all dimensions drawn from an origin, or have dimensions drawn as widths within individual features, the former is only useful for people machining (with a DRO) but makes it impossible to make changes to the plans, you have go back to a drawing and dimensioning strategy where each feature has its own relative dimensions and the location of that feature is a separate and easily changeable dimension.
So yes I do often make a for-at-the-milling-machine-only drawing with dimensions all from the same origin, but that's not how I draft when I'm designing, nor would it be what I'd make available as plans for my engine designs (the for-at-the-milling-machine-only might be in an appendix to the plans).
HTH, IMHO, YMMV, VWPBL, yada, yada, yada...
A related topic is whether plans should have all dimensions drawn from an origin, or have dimensions drawn as widths within individual features, the former is only useful for people machining (with a DRO) but makes it impossible to make changes to the plans, you have go back to a drawing and dimensioning strategy where each feature has its own relative dimensions and the location of that feature is a separate and easily changeable dimension.
So yes I do often make a for-at-the-milling-machine-only drawing with dimensions all from the same origin, but that's not how I draft when I'm designing, nor would it be what I'd make available as plans for my engine designs (the for-at-the-milling-machine-only might be in an appendix to the plans).
HTH, IMHO, YMMV, VWPBL, yada, yada, yada...
I understand what you mean about a pre-written set of instructions being too bothersome. I think it would be hard to create a general solution since people all have different tools and preferences. My challenge is just getting some basis for the suggested order of operations. I just am too new to machining and need help getting started.
Like all of us I am always learning and the notes help me during the design & fabrication. Also, as I submit a number of my projects for publication and I know that no everyone who reads the articles and could be interested in making the parts may not be as familiar with the process as I am.
peterl95124
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Yes, we were all "new" at some point, and needed help in one way or another, welcome to the club, I hope you enjoy the journey !
get Kozo Hiraoka's book "Pennsylvania A3 Switcher, first project for beginner", its *perfect*, with good technical drawings including both plane views with dimensions and 3-D (from an angle) views to see what the part actually looks like or how a set of parts go together, lots of photographs, and the text is well written without too much boring do this followed by do that, its more about explanations where needed. when a part is too complicated Kozo will make drawings of the part at intermediate steps, so the correct order of operations is plainly obvious (one of the reasons I say its *perfect*).
I got the book and built the engine, and I learned enough that I was then able to draw/design and build a "Baldwin 4-4-0 American" just from photographs, no plans, no instructions.
the most important aspect to figuring out order-of-ops on the lathe is which end of the part requires the most accurate concentricity of cuts, do that one first, then when you flip the part around to finish the other end it won't end up perfectly concentric (esp in a 3-jaw chuck) but this is the end of the part where that least matters, and for milling what needs to be though out is how will the part be clamped in the vise and from where will you be making your offsets for your operations.
get going, start filling up that box of rejects that we all have (I have multiple such boxes
) and don't let mistakes get you down, they're just learning experiences, join a local club if there is one as this can help overcome frustration, I've gotten an uncountable number of good suggestions from my fellow BAEMClub members, and it seems that no matter how many models I've built I'm always having to do something I've never done before.
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