J
JorgensenSteam
Guest
I have the Alibre 3D modeling program, but there seems to be a big transition from the typical 2D drawings to the 3D modeling, especially when changing from one programming company to another.
Help Support Home Model Engine Machinist Forum:
JorgensenSteam said:
2D sketches are created from 3D parts. When you create a 3D part and have it saved, open a new drawing and the part will be completely drawn in 2D for you. All you have to do is dimension it. You can even have Alibre import the dimentions from the 3D drawing then weed out the ones you dont want.
I struggled with 3D at first but it is very easy for me now. 2 years of practice. I only use about 20% of what it can do and have no trouble drawing anything i want. Stick with it and you wont be sorry.
Have you been able to draw anything in 3D yet?
JorgensenSteam said:
What do you mean by "initial sketches"? Are you trying to draw in Alibre in 2D? You should never have to draw in 2D. You can make the 3D model first and then make a 2D drawing from the 3D model. Is that what you are doing?
JorgensenSteam said:
That is the problem. Give me an hour and i'll start a thread and draw a simple part and then create the drawing. How about a simple flywheel with 6 holes to create the spokes.
Turns out I don't have an hour. I have to go out tonight with the wife. The easiest way to do this is to make a PDF file with some basics and drop it in the file section. That way I can put text and pictures together. After that a thread can be started and questions can be asked specific to things you may not understand.
I am in any way an "expert", in fact i concider my self a novice in the way that I don't use 20% of the power of this program. I use the standard version and there are 2 other versions that have even more power.
I hope to have something put together tomorrow and i will post a "heads up"
I am in any way an "expert", in fact i concider my self a novice in the way that I don't use 20% of the power of this program. I use the standard version and there are 2 other versions that have even more power.
I hope to have something put together tomorrow and i will post a "heads up"
I've been using Alibre for several years and like it. I sketch cross sections in 2D sketch then extrude them into 3D solid parts. Cuts, holes, etc are also sketched in 2D and extruded, rotated, or whatever to modify the 3D solid. From the 3D model I then create the 2D dimensioned drawing for the shop. Maybe I'm missing something here. Steve, do you create your 3D solid, from scratch in 3D sketch mode? It was my understanding that 3D sketch was used for creating guide curves for lofts, sweeps, spirals, ect. I could be wrong.
"Learn 3D CAD, Intorduction to solid modeling" by Ron Bowes, is a good reference for Alibre. I don't have the link handy, but the book has been mentioned not too long ago on this forum.
There are other Ailbre users in the group. I look forward to the thread as I'm sure I'll learn something.
Regards,
Chuck
"Learn 3D CAD, Intorduction to solid modeling" by Ron Bowes, is a good reference for Alibre. I don't have the link handy, but the book has been mentioned not too long ago on this forum.
There are other Ailbre users in the group. I look forward to the thread as I'm sure I'll learn something.
Regards,
Chuck
kuhncw said:
I think terms are getting confused here Chuck. From what I have read here I think the problem might be that Mr. Steam is having a problem using the Extrude Boss and Extrude Cut buttons. My intent will be to explain the very basics of getting started and show how to make a simple part using the boss and cut buttons. Draw a circle and extrude it, then draw on the circle and cut a little off. You know what i mean. Just a little jump start in thinking 3D. Once you get that, you can add to the learning as you go.
See what i'm saying?
deere_x475guy
Well-Known Member
Pat have you tried going through the tutorials?
Here is the disk brake rotor tutorial I did. The dimensioning isn't finished on this but you should get the idea.
Here is a part I drew up that I had alread built..
Edited to fix my screw ups...I can't multitask....I have a part in the anodizing bath to baby sit also..
)
Here is the disk brake rotor tutorial I did. The dimensioning isn't finished on this but you should get the idea.
Here is a part I drew up that I had alread built..
Edited to fix my screw ups...I can't multitask....I have a part in the anodizing bath to baby sit also..
)Steve, we are both on the same path. I think sketches and drawings were getting confused.
Creating the model is a bit like machining the part in a lot of ways.
Regards,
Chuck
Creating the model is a bit like machining the part in a lot of ways.
Regards,
Chuck
deere_x475guy
Well-Known Member
Pat, I just did a slight modification on this part..the extrusion hole now cuts through everything.
Damn...let me figure out how to insert the file back to you in the post...brb.
Ok..got it.
View attachment Sample-Cylinder-01.AD_PRT
Damn...let me figure out how to insert the file back to you in the post...brb.
Ok..got it.
View attachment Sample-Cylinder-01.AD_PRT
Dave Sohlstrom
Member
- Joined
- Oct 4, 2008
- Messages
- 195
- Reaction score
- 27
Pat
You of course know that there are three parts to Alibre. Parts, assemblies, and drawings. You also know that you start by making parts. Fly wheel, crank, cylinders. connecting rods etc. From parts you can tell Alibre to build you a 2D drawing. You then choose the views you want. Front, top, side etc. You can then dimension those drawings, print them and take them to the shop and build them. The other thing that you can do is build assemblies using the parts you have built. You can also make a Drawing of this assembly. When building assemblies you constrain parts so that if you rotate the crank shaft the piston will move up and down and the valves will move. You can ask Alibre to check your assemble for interference. If the cylinder bore is 1" and the piston OD is 1.002" Alibre will tell you you have a problem.
You also know that Parts are build using a series of sketches. Sketches have to be closed in order for them to be turned into a solid or in order to remove material from a part. Any line, arc, circle etc that you sketch can be dimensioned so say you sketch a circle 2" dia and need 2.005" just dimension it and it will change to that size
Keep plugging away at it and it will come. Keep asking questions and folks will try and help. If you do a part that you are having trouble with post the Alibre part file here so others can download the part and see what could be done differently or find the problem.
What version of Alibre are you using. Version 12 is the current one so any earlier part would be updated to 12 in my case so you would not be able to open it again.
Dave
You of course know that there are three parts to Alibre. Parts, assemblies, and drawings. You also know that you start by making parts. Fly wheel, crank, cylinders. connecting rods etc. From parts you can tell Alibre to build you a 2D drawing. You then choose the views you want. Front, top, side etc. You can then dimension those drawings, print them and take them to the shop and build them. The other thing that you can do is build assemblies using the parts you have built. You can also make a Drawing of this assembly. When building assemblies you constrain parts so that if you rotate the crank shaft the piston will move up and down and the valves will move. You can ask Alibre to check your assemble for interference. If the cylinder bore is 1" and the piston OD is 1.002" Alibre will tell you you have a problem.
You also know that Parts are build using a series of sketches. Sketches have to be closed in order for them to be turned into a solid or in order to remove material from a part. Any line, arc, circle etc that you sketch can be dimensioned so say you sketch a circle 2" dia and need 2.005" just dimension it and it will change to that size
Keep plugging away at it and it will come. Keep asking questions and folks will try and help. If you do a part that you are having trouble with post the Alibre part file here so others can download the part and see what could be done differently or find the problem.
What version of Alibre are you using. Version 12 is the current one so any earlier part would be updated to 12 in my case so you would not be able to open it again.
Dave
Dave Sohlstrom
Member
- Joined
- Oct 4, 2008
- Messages
- 195
- Reaction score
- 27
Pat
I downloaded steam chest, base plate, cyl head, and cyl.
The one thing that I see common to all the parts is that you have your units set to 4 decimal places 5 would be better. You also have your spinner set to .1" .03125" would be better.
Cyl head is not a closed sketch. you need to remove the vert line and small circle at the top. Also sketch OD and ID only the extrude boss to the thickness required. Then do a second sketch for the recess and do a extrude cut.
Dave
I downloaded steam chest, base plate, cyl head, and cyl.
The one thing that I see common to all the parts is that you have your units set to 4 decimal places 5 would be better. You also have your spinner set to .1" .03125" would be better.
Cyl head is not a closed sketch. you need to remove the vert line and small circle at the top. Also sketch OD and ID only the extrude boss to the thickness required. Then do a second sketch for the recess and do a extrude cut.
Dave
Dave Sohlstrom
Member
- Joined
- Oct 4, 2008
- Messages
- 195
- Reaction score
- 27
JorgensenSteam said:
You get a drawing like that by drawing every individual piece and then putting them together on screen.
One thing I notice from your drawings is you are trying to draw the entire part in one step. Take a flywheel. First i would draw the wheel as a solid circle. Then I would cut out the recesses on both sides. Then cut the hole thru the center. Then cut out the spokes, ect!
You dont have to do it all in one step.
Here is a flywheel I did for a guy. Use your mouse and move the blue dog bone looking thing up and down to see what steps I took to get to the final product.
View attachment Ron\'s Flywheel.AD_PRT
- Joined
- Dec 2, 2008
- Messages
- 971
- Reaction score
- 9
Pat
In the last year or two I have gotten fairly comfortable with Alibre' but I still remember the startup difficulties. One of the techniques that has been helpful to me is to construct a part the same as I would in the shop. In the shop, I have a Lathe and a Mill. I do not have an extruder. I try to limit my use of the solid extrude function since I can't do that in the shop. I will use it to extrude a round or flat bar that represents the raw material that I will start the actual machining process with.
After that, all modifications are done with the "revolve cut" function (lathe work) or with "extrude cut" (milling ). Rarely, I use the "loft cut" function which can also represent milling. It may not always be the quickest way to construct the part in Alibre but it is a tremendous help in planning the steps to produce the part in the shop.
For example, in your crankshaft, you start out with an extruded rod representing one end of the shaft. If you are going to make a built-up crank with the webs brazed or welded to the rod, that would be the way to start. The rod is the first piece of raw material. But the crankshaft would be made of 5 parts in an assembly.
If the part is going to be turned from bar stock, either round or flat, my first extrusion would be a piece of bar. On one end of the bar, I extrude cut two small circular depressions. One to represent the shaft center and one to represent the center of the crank throw. I would then use these to create axes parallel to the length of the bar. Switching to the side view, I would draw a rectangle and revolve cut around the throw axis. The next step would be to draw two rectangles and revolve cut them around the shaft axis.
This directly follows the cuts you would make on the lathe. There are a few things to remember. The first extrusion should be centered on the Z axis. If you are starting with a round bar, the Z axis is the center of the circle. If you are going to start with a flat bar, the rectangle should be constructed so that two sides are equal distant from the Z axis (constraint) The rectangles that are used to draw the revolve cuts must be drawn on the ZX plane, not on the face of the bar. The dimension of the shaft and the throw are determined by the dimension between the corresponding axis and the nearest side of the pattern rectangle.
I hope I made that clear. I will attach an example.
One thing I noticed on your drawing is the nice radiused edges on the crank webs. That is too easy to do with Alibre but think about what it would take in the shop. You might decide that you don't want to do that.
I hope this helps.
Jerry
View attachment crank example.AD_PRT
In the last year or two I have gotten fairly comfortable with Alibre' but I still remember the startup difficulties. One of the techniques that has been helpful to me is to construct a part the same as I would in the shop. In the shop, I have a Lathe and a Mill. I do not have an extruder. I try to limit my use of the solid extrude function since I can't do that in the shop. I will use it to extrude a round or flat bar that represents the raw material that I will start the actual machining process with.
After that, all modifications are done with the "revolve cut" function (lathe work) or with "extrude cut" (milling ). Rarely, I use the "loft cut" function which can also represent milling. It may not always be the quickest way to construct the part in Alibre but it is a tremendous help in planning the steps to produce the part in the shop.
For example, in your crankshaft, you start out with an extruded rod representing one end of the shaft. If you are going to make a built-up crank with the webs brazed or welded to the rod, that would be the way to start. The rod is the first piece of raw material. But the crankshaft would be made of 5 parts in an assembly.
If the part is going to be turned from bar stock, either round or flat, my first extrusion would be a piece of bar. On one end of the bar, I extrude cut two small circular depressions. One to represent the shaft center and one to represent the center of the crank throw. I would then use these to create axes parallel to the length of the bar. Switching to the side view, I would draw a rectangle and revolve cut around the throw axis. The next step would be to draw two rectangles and revolve cut them around the shaft axis.
This directly follows the cuts you would make on the lathe. There are a few things to remember. The first extrusion should be centered on the Z axis. If you are starting with a round bar, the Z axis is the center of the circle. If you are going to start with a flat bar, the rectangle should be constructed so that two sides are equal distant from the Z axis (constraint) The rectangles that are used to draw the revolve cuts must be drawn on the ZX plane, not on the face of the bar. The dimension of the shaft and the throw are determined by the dimension between the corresponding axis and the nearest side of the pattern rectangle.
I hope I made that clear. I will attach an example.
One thing I noticed on your drawing is the nice radiused edges on the crank webs. That is too easy to do with Alibre but think about what it would take in the shop. You might decide that you don't want to do that.
I hope this helps.
Jerry
View attachment crank example.AD_PRT
Pat, I took a look into your Sample Cylinder. The main thing I'd do differently is to move Plane 5 out from the center plane by the length of the steam chest projection. Sketch the chest on Plane 5 and extrude the boss back to the cylinder surface. Other than that, you made a pretty good solid model.
Keep asking questions and keep working on the Alibre. You'll get there.
I'll try to attach my modification of your sample cylinder. Attachments are new to me, so I may mess it up.
Regards,
Chuck
View attachment Sample-Cylinder-002.AD_PRT
Keep asking questions and keep working on the Alibre. You'll get there.
I'll try to attach my modification of your sample cylinder. Attachments are new to me, so I may mess it up.
Regards,
Chuck
View attachment Sample-Cylinder-002.AD_PRT
