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ptc-49828181-Visitor
1-Visitor
August 31, 2014
Question

How to flatten the inner vanes of transit mixer drum

  • August 31, 2014
  • 7 replies
  • 4832 views

I have been trying to create the inner vanes of transit mixer drum. As you can see in the images one vane is clockwise and the other vane is anticlockwise which has been color coded green and yellow respectively.

The problem is that:

I am unable to flatten the inner spiral and hence unable able to get developement length of the inner vanes nor the inner and outer diameter of the vane in such a way that after cutting/dividing the vanes in sections for example at an angle of 120 degrees,

since in real world the sheetmetal has to be cut in sections either by laser or plasma cutting and then twisting each section by beating with hammer and then welding it on the inner periphery of the drum inorder to take shape of a spiral.

The inner and outer diameter and flat pattern of each section of the vane is required after flattening it since it has to be sent for laser cutting in 2d

I have been try to find a solution for days but have been unsuccessful so far please help me out


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7 replies

TomD.inPDX17-Peridot
17-Peridot
August 31, 2014

This is a perfect case for Flatten Quilt. Divide each piece as you want them cut, place a point along a flat edge, and use the default settings.

You will find there is not a simple "radius" for a solution. You can obviously overlay a radius to see how close it is, but you will likely need DXF files to get the right shape.

Setting up the views is a lot of work. You will be repeating this process quite a few times. Be patient and set up a reliable routing for your entire process. Then get busy.

You might also mark each piece with an identifier. You will loose track with so many similar pieces.

Welcome tot he forum, Akshay!

BTW, this is a double start helix both in the same direction. They are both clockwise.

ptc-49828181-VisitorAuthor
1-Visitor
August 31, 2014

Oops Sorry,that is a double start helix in the same direction I meant the the drum rotates clockwise and anticlockwise thankyou for correcting me .I am a beginner to creo so can u give me an example what exactly do u mean .I will share my .prt file

thankyou

ptc-49828181-VisitorAuthor
1-Visitor
August 31, 2014

Firstly how do divide the inner vanes into section of 120degree and how to flatten quilt FYI I have created the model in solid modelling .

TomD.inPDX17-Peridot
17-Peridot
August 31, 2014

Most times it is not the operation that is a challenge, but the technique.

If you wish to manufacture this, you may want to do this as an assembly with each plate modeled separately.

Here is a surface copied from the helix. It was merges as a complete helix (sometimes these surfaces disconnect). And then the trim made a 1/3 rotation of the 1st spiral. A point was added to the edge of the new quilt. The flatten quilt was used using the 1/3 rotation quilt and the point.

Since flatten quilt has to make some determinations, you will notice that the ends are somewhat distorted. Measure the length of the edges of the flat quilt to see if the outcome is what you expect from measuring the length of the original edges.

flatten_quilt_drum.PNG

TomD.inPDX17-Peridot
17-Peridot
September 1, 2014

This was of particular interest to investigate further.

I used my own dimensions in order to understand the ramifications as this is quite important for such a large project. This is certainly worth creating a scaled mockup to test the validity of the data obtained form the CAD model.

In the video, I added a few techniques that will help assure proper development:

1) Distortion of Flatten Quilt is sufficient in this instance to change the straight forward technique.

2) Ensure the developed edge in the helix is the same as the developed edge of the flat pattern.

3) Use a single flatten quilt edge to develop the form with a consistent width using a second sweep.

The deformation of the initial quilt was significant. I opted to use only the interface edge between the helix and the barrel. Then confirm the edge length before sweeping the actual "shelf" width. This process should minimize the expected distortion. Talk with your fabricators and see if I'm on the right path.

I opted to flatten a complete 360 degree section... twice. If the intent is to only flatten 1/3 (120 degree) sections, this should be managed in a similar way by dividing the initial helix at each 120 degree segment. Don't try to do this on the 360 degree flat quilt. Smaller segments may be more accurate. I don't know the tolerable level of inaccuracy for this type of feature, or how the helix will be formed.

I know you are using an older version of Pro/E so adding the model won't help you. I believe all the features I am using are available in older versions. Some of the features are completely different in their usage (like the intent edge reference) but it is there under a different feature type. Regardless, I hope the intent of my usage for these features are clear if you need to find a work-around.

Making the drawing is another matter. I suspect you will need to create a DXF for the fabricators. You can move the relevant features to layers to manage the views. You can use the flat planes to create view orientations. Again, this is probably easier as an assembly.

I made this as a part. It did have some trouble merging the barrel with the helix. Too many coincident edges I presume. I finally used a revolve surface; offset surface; and thicken just shy of intersecting. See the last 3 features in the image below.

Good luck and let us know if you need more specifics!

mixing_barrel.PNG

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