Digitize plans / prints on a CNC machine?

[TomA]

Is there some way to digitize a print / plan on a CNC machine? Replace the cutting head with a stylus that can be viewed, jog it around the plan with a joystick and output the x and y coordinates when a button is pressed on the joystick. The strings of coordinates would have to be processed into cutting directions.

Tom Alborough

 

[wet feet]

Realistically, no there isn't. It wouldn't be impossible to use a stylus or sharp engraving tool to locate intersections of lines, or even a kind of offset table from the coordinates on the controller screen-having aligned and secured the drawing. You would then have to scale them to the correct size for the vessel in question and create vectors that join the points in the manner that the designer intended. It would be easier to use a digitising tablet, if one is available, and then to do the drafting. A stylus on a Faro arm would be another alternative. None of these methods are less labour intensive than measuring the points and scaling them the traditional way. The only thing that should be avoided is those "miraculous" scanning programs that promise to create dxf files from a scanner's output. They lead to hundreds, or even thousands of blobs and skinny outlines that take an eternity to clean up

 

[TANSL]

I do not see clearly what information you have and what final result you want to achieve. I assume, and forgive me if I am wrong, that you want to obtain a traditional drawing from the information that the CNC machine uses to cut. If so, it would be necessary to know the format of the cutting file. In many cases it is a dxf file that, when taken to a CAD/CAM software, is automatically translated into a drawing. If what you have is a cutting file in machine language, the issue is more complicated but could be resolved.

 

[TomA]

This would address the situation where a paper print or plan existed but no cutting file.

 

[TANSL]

So, and please excuse my clumsiness, do you have the cutting file for the machine or what do you have now and what do you want to achieve? Thank you for taking the time with me.

 

[TomA]

Good questions!

I only have a paper plan. I could trace out the individual components onto wood and cut them out by hand but I would rather digitize the outline of each component and let my cutting machine of choice do the cutting.

A digitizer tablet would do the job but they are expensive for the size needed. A CNC machine could also do the job; the X and Y steppers know where they are on the cutting surface and could be jogged around by a joystick while tracing out a plan. Points could be dropped and saved while tracing out each part. The components would need to be processed into cutting file(s).

 

[TANSL]

Could I have a copy of the plan you have? I may be able to provide a solution, depending on the quality of the plan, the format (tff, pdf, gif, ...), whether it has become deformed over time (copies were previously made using machines that emitted heat and slightly deformed the copied shapes), whether clear references can be taken to allow the correct scaling of the pieces, etc.

 

[Herreshock]

Is there some way to digitize a print / plan on a CNC machine? Replace the cutting head with a stylus that can be viewed, jog it around the plan with a joystick and output the x and y coordinates when a button is pressed on the joystick. The strings of coordinates would have to be processed into cutting directions.

Tom Alborough

This can be done with a circuit board like duet wifi so you could play different things, also you can unhook the same board to plug in a lathe,3d printer, etc just by changing the sd card

 

[TomA]

Um, I would rather not part with a copy but thank you for the offer.

I believe this should already be done somewhere or, should be doable:

-- Trace out each component with a stylus, joystick and "button" on a CNC machine.
-- Turn each component into a series of vectors.
-- Lay out the components onto a sheet of wood.
-- Cut the components out.

 

[Herreshock]

You can install duet wifi or any other tweakable circuit board to an existing proprietary machine, using the same stepper or servo motors maybe just changing motor controllers or sensors but anyway its easy and cheap to do

Search online cnc forums and YouTube and publish your solution, this probably has been done

 

[wet feet]

I would really recommend that you try holding the plans securely in place,ensuring the datum lines are straight and just lifting the dimensions.I don't know how extensive the experience of using CNC machines may be among other contributors but i do have tens of thousands of hours of CNC programming and usage and hence a quite good understanding.I am acquainted with a machine that can mount a camera for moving around an area and selecting points of interest.Such an adaptation to a purely cutting machine wouldn't be instant or cheap.Additionally any points picked up by any method at all will have any errors multiplied by the scale factor,unless you are building a model yacht and have full scale lines.So you will find yourself having to loft the points to arrive at useable lines-whether on a board,computer or loft floor.Then if building is contemplated you will have to offset by the proposed hull skin thickness.So all in all a huge amount of work ahead whatever your choice,alternatively a fair sized bill for somebody to do the work for you.

 

[Herreshock]

No need for that CNC services scam to be honest, a duet wifi cost 50, and few nema23 or nema32 motors can be used, even second hand and building a structure with UHPC concrete for the base and aluminium doors profiles for the gantry.

CNCs are really easy to build but again a hand mill works as well just by printing the planes, that can even be done by a regular a4 printer and joining the papers as a mosaic

But again this requires teamwork in a garage, people shouldn't do these projects alone while exploiting others

 

[Tops]

@TomA ,If this were my project, I would scan or take flat photographs the prints and use them as an underlay, scaled to real world size, and draw over the top of them in CAD, using the values on the print and the CAD system to correct for any graphic issues on the images. Then nest and run through CAM to get to the CNC.

I do understand the ask: I have a CNC machine, I do point to vector conversions in CAD...but I would be concerned in this case about the accuracy of sighting multiple points on the paper to the probe on the CNC followed by the time and effort to make and prove out the data conversion system.

 

[wet feet]

If I feel a need to discuss CNC construction I usually go to www.cnczone.com there is a huge amount of knowledge there.Designing and building a complete machine is quite a big undertaking,and unless you have lots of future plans to use the machine,a disproportionate amount of effort when people with machines that are ready to go are out there and happy to help.I did watch the promotional video for that duet controller but when it was said in voiceover that the it doesn't accept the full range of Gcodes and would have to have a post processor custom written I stopped.My hobby machine runs LinuxCNC and does enough to work at no cost for the software.

I have no idea what size boat the OP is working with and if he believes that tracing a print of an original drawing is particularly accurate there may be a surprise in store.I suspect a small boat is involved as most larger boats will have a set of hull lines and an offset table which are used to create a fair set of lines at full size and from which a plank thickness deduction will need to be made.

Turning a set of points into anything useful for CNC work does involve a bit of understanding and I would have big doubts about any file presented to me being ready for use.Which would require me to verify that no gaps exist between the entities that define a piece's boundaries.The we arrive at the point where CAM software and it's limitations may affect progress;most hulls are defined in part by splines and not all software can deal with splines.This is a limitation most often encountered by lower cost or legacy programs and they may seek to convert splines to arcs with a chordal deviation that the user can select.At which point the tool trajectory will feature segments of circles and thus further degrade the accuracy a little more.It may not be significant on a small and simple boat but by now we have probably deviated quite an amount from what the designer intended.

An up to date design office will be using 3D models of the boat and can supply accurate data for the inner surfaces,which can be depended on for accurate results when cut directly.I expect our large ship contributors will routinely send files directly to plasma cutters and the leisure market increasingly works from moulds that have been taken from 5 axis machined plugs.

 

[Herreshock]

Even big boats hull curves plans can be drawn manually just with 2 straight aluminum profiles to place x,y coordinates points and a bended strip of wood to find and draw the curves between these points whil i use the arch tool a lot when drawing sailboat hulls on sketchup, usually a hull cross sectional face has few curves that can be drawn with a bending strip

Pretty easy probably it can be done in an afternoon, and don't forget to use free software for g-code