Lines in Pro/E

I've been using Philip Bolger's offsets for "SEGUIN" while I learn to use Pro/E Wildfire as a boat modeling tool. When I put the surfaces on I get some distortion in the upper bow area so a little point shuffling is still in order.

A fair surface from scratch is much easier to produce than a fair surface from offsets, but I suspect I could produce fair surfaces from scratch for the rest of my life and never produce lines any sweeter than these.

Doug Carlson

 

A more ambitious project in Pro/E

This is a more ambitious project that still needs some work. I intend to produce a scale replica using Pro/Manufacturing and our 3 1/2 axis cnc horizontal mill when I'm satisfied with the surfaces.

Doug Carlson

 

nice lines Doug, keep me informed!
whats a "3 1/2 axis cnc horizontal mill" ?

 

Yipster,

A milling machine has a powered spindle (1/2 to 30 hp or more).

The spindle holds a fluted, rotary, cutting tool that removes material by creating chips as it is brought into contact with an object. Its the same mechanism as a woodworkers shaper or a hand held router. The cutting tools can have a variety of geometries including cylindrical or conical sides with a hemispherical end ("ball nosed end mill") which is primarily used for contouring 3-dimensional objects such as boat molds.

The material or object from which the chips are removed is clamped to a table that is integral with the base that holds the spindle.

In a standard or vertical milling machine the spindle is oriented vertically. The table can be moved horizontally along two perpendicular axes that lie in a plane perpendicular to the axis of rotation of the spindle. Also, the spindle can be lowered or the table raised thereby creating cartesian x,y,z(spindle axial) motion.

In a horizontal mill the spindle is oriented horizontally and one of the table motions is vertical. Horizontal mills tend to be used on larger and heavier parts as the horizontal orientation of the spindle is conducive to higher rigidity in the machine frame.

If a rotating table is placed on the xy table a 4th axis of motion is created.

If a tilting table is placed upon the rotating table a 5th axis of motion is created.

The 4th and 5th axes of motion can also be achieved by gimballing and rotating the spindle or quill. This is the typical arrangement in the huge gantry mills used for creating boat plugs and molds, large aircraft components etc.

There are several other forms of articulation used to create 6, 7 and more axes of motion in some machine tools such as filament layers in composites manufacturing and process robots for welding, painting, etc.

Computer numerical control means that the movement is controlled by computer generated input, paper tape in the old days, networking or DNC today.

In computer controlled machines, if 2 axes can move simultaneously it is considered a 2 axis machine. If the spindle can be raised and lowered relative to the part by computer control but not at the same time as the other 2 axes are in motion that is considered 2 and 1/2 axis. Perfectly adequate for drilling, boring, pocket milling etc.

On some older machines it was possible to switch from simultaneous xy motion to simultaneous xz or yz motion. The end result of 2 axis machining tends to be a topographic map or tiered wedding cake effect if contouring a part. Contouring is all that those of us who like boats really care about.

If 3 axes can move simultaneously you have 3 axis motion. True contouring is practical with 3 axis motion. There are limitations to accessing undercut or hidden areas however. A 4th axis allows the other 3 to effectively move around the object being machined to gain additional access. If the 4th axis can function simultaneously with the other 3, you have a "true" 4 axis machine. If the rotary motion is computer controlled but not simultaneous, 3 and 1/2 axis or 3 axis with an integral indexing table.

Five axis motion allows for even better contouring in nooks and crannies but is still often limited by range of motion of the 4th and 5th axis and limitaions of cutting tool reach etc.

I apolgize if told you things you already knew.

Doug Carlson

 

You are licky. Last five years I use offsets or preliminary lines.

 

Doug -

I have been thinking about migrating to ProE /Wildfire (but not too seriously). What sort of tools does it have for checking spline or surface curvature? Any of the "curvature curve" or 2nd derivative checks like you see in most hull design programs? Gaussian or mean surface curvature color gradient maps? Or is it all done "by eye?"

Chris Krumm

 

Pro/E curve and surface analysis

Chris,

The analysis tools you refer to are available in Pro/E.

My day-to-day activities don't require me to use them however, so I can't give you an assessment of their functionality and because I have no experience with any of the dedicated boat design softwares, I can't make a comparison.

I have the "advanced surfacing package" in Pro/E primarily because I take in advanced surface models from customers for manipulation, fixturing, and machining. My job is not to analyze their surfaces only to reproduce them in plastic, modelling board, aluminum, or steel.

The surfaces module is a fairly pricey add-on and I believe the analysis tools are part of that package rather than the basic or "foundation package".

I am just beginning to use the analysis features in my afterhours pursuit of boat design. I will post my experiences and results as I progress.

Doug Carlson