Making frame drawings and its adoption to laser cutting

[Kiyoo Iizawa]

Hello everyone,

 I am posting for the first time. Please forgive me for my uncertain English.

 With regard to creating the precise 3D graphics images,　I am far from Denis's amazing graphics in Swan class 3D modeling. However, using a similar 3D graphics software, my attempt here is to create line data, i.e. frame drawings, from that 3D curved surface.

 Many 3D graphics software output formats are raster data, i.e. gathering of the small dots, but drawings such as CAD we use for part machining are consisting of vector data, i.e. line shapes represented by mathematical formulas. They are not compatible because they are completely different data.

 

 But looking at the graphics image like below, wouldn't you wish to make each shape of this frame to an accurate drawings? It is the software that I am using that enables it. In other topics such as “JPG to CAD” are also being discussed this kinds of matter, but I think this method introducing here is also one of the way to do it.

 

 If such an indefinite shape can be made into an accurate drawings, it is expected that drawings making and parts processing in scratch build will become much easier.

 I would like to introduce the outline of this method by continuous posting. I wish you will be interested in this approach.

 

Because it is difficult for me to provide instant English sentence according to the situation, I am preparing outline description as a document. To identify the document part and the daily conversation, I use document text with green color so that you can easily pick up only the document part.

 

[Kiyoo Iizawa]

1. Brief Introduction

 The method introduced here is a system that (organically) combines 3D graphics software, 2D graphics software, and laser cutting machines to innovatively shorten drawings making and part machining in scratch builds.

 First, to make the drawings for ship modeling, the most people are using CAD for drafting them but I see very few cases that it contains individual accurate frame drawings. In my case for several reasons, I am using the graphics software to make frame drawings as well as various parts drawings. The reasons are,

 1) Many of the parts such as individual frames are consist of free line of shape which cannot easily be defined by numeric but the graphics software which I am using can rearise them accurately by one of its feature (Bezier curve etc.). The Bezier curve itself is vector data, it later plays a major role in creating the drawings.

 

 2) 3D graphics software using Bezier curves can draw free curved surfaces with fewer line information and can be edited its shape intuitively and smoothly within a short time.

 

3) In this software, once a curved surface has been created, you can generate new line shape (rather than drawn) by slightly drag the desired location. This line can be used as a new frame line.

 

The first figure below is the line shapes of the Body Plan drawn in this software and the second figure shows hull curved surface generated from these line shapes. The third figure shows the generated new frame lines on the hull surface and the fourth figure shows their individual line shapes.

 

 

Cont.

Kiyoo Iizawa

[druxey]

This looks to be an interesting process. In terms of time taken, can you give us some idea of how long it took to generate the project to this point?

 

Thanks, and looking forward to further instalments!

[Kiyoo Iizawa]

Hi druxey,

Thank you for the inquiry.

It's hard to estimate the overall time. In particular, the time to become familiar with the basic operation of the software depends on each person. This explanation is all but the learning time.

In my case, I first create an accurate template from plan etc. on the 2D soft side. Once you get used to software, a day or two will be enough.

Next, I take it into the 3D software and draw a typical frame line. This is possible in 1-2 hours because it only traces few lines of the template.

The third produces a curved surface of the hull based on it. Fixing the distortion of the curved surface depends on people's satisfaction, but it's still enough to take hours or days.

When you satisfied the curved surface, a new frame line can be generated at the desired position on it as much as necessary. This is only click (drag) action, so you can do it in a few hours. This is the state shown in the last two figures of my last post.

 

I will continue more post for details, but I will say my achievement is 1-2 weeks in total if I only create frame drawings, and 1-2 months if I include all parts and assembly drawings including data for laser cut.

I hope this is right comment for you.

 

Kiyoo

 

[Mark P]

Thanks for posting this Kiyoo;

 

It is all very interesting, and I look forward to learning more about your process. I can see that I need to learn this 3D stuff (I need it for work as well, so good reason to do so!)

 

All the best,

 

Mark P

[Jaager]

Kiyoo,

 

Congratulations, you have developed a way for a computer to do do what I had hoped, in vain, 3D CAD would do - extract individual frame and bend shapes and - I assume this is coming - isolate them as freestanding layers.  An easier and much faster way to get patterns for scroll cutting.

 

The moulded shapes - how many patterns along the way are needed to get a proper inside shape?  

 

The computer controlled cutting is an entirely separate stage.   Finding a near automatic way to to convert the data to the necessary formulas is a big deal.  Is it something that can gain you  proprietary rights and royalties?

I am still skeptical about the practicality of a laser cutter for a one-off hull, or as something that is cost effective for an individual modeler.  For the manufacture of components for a kit, I see the laser cutter ( or plasma, or water jet, or whatever the eventual winner tech will be for CNC cutting )  as essentially imperative.  It looks as though you have discovered a way to significantly reduce the development time.  This is potentially a big deal, is my thinking.

[PietFriet]

Isn't this what people have been doing for years with Delftship? Maybe I'm missing the point.

[Kiyoo Iizawa]

Thank you for many comments.

 

Hi Mark P,

In fact, I have already prepared a step-by-step manual that explains the steps from learning software to actual creation work. It seems to be the best for learning this method. Please wait until I finish writing this topic on how to make it open.

 

Hi jaager,

This is an easy and much faster drawing method as you say to create accurate shapes at scaled size, correction drawings according to various processing machines, etc.

 

The number of lines for inside shape is as good as 10 when creating the outer shape. Actually, the lines drawn with the outer shape are copied and shifted the control point inward by the thickness according to the height.

 

In case the laser machine I am using in rental shop, the data machine recognize can still be used in Illustrator format. Therefore, there is no malfunction due to conversion. As far as I know, laser cutters seem to be able to use 2D graphics data such as Illustrator, CorelDraw, etc. as they are.

 

If this can be said to be a development product, I want to have ownership. However, the purpose of my posting on this topic is because I want anyone to use this technology openly. I think there are some things that need to be addressed for that. I'm old enough.

 

At first, I was skeptical about the use of lasers, especially for scratch builds, but since the advantages are much greater than the disadvantages, I put them to practical use after considering how to avoid the disadvantages.

Workarounds will be described soon in this topic.

 

I actually designed a part equivalent to one structural model kit, processed it with laser cut, and am currently in building for verification. I have cut over 1,500pcs of parts within 8 hours. This picture is hull made parts by laser cut (just lightly sanded to remove burn mark). Also the cross section that took out some of it is my thumbnail.

 

To evaluate this method, please read this topic until it is over. I hope it will meet your expectations.

 

Hi PietFriet,

I have no knowledge of Delftship at all, but I think it can be used if it is software with similar functionality to the 3D graphics software I use. It is a free-form surface creation function by Bezier curve and numerical control function for dimensions and coordinates.

 

Thanks again,

Kiyoo

 

 

[Kris Avonts]

Hi Kiyoo,

 

This looks a nice and elegant way of creating the required lines for frame timbers.

I'm however quite surprised regarding your effort estimation as you have given in reply to Druxey's question.

If I look at my own efforts, I would rather spend months instead of days to reach that state.

Well done!

May we also get a clue about the specific drawing software (both 2D and 3D) that you are using?

I'm a fan of FreeCAD, mostly because it is 'free' in every sense.

 

best regards,

   Kris

[Kiyoo Iizawa]

Hi Kris,

Appreciate the ratings. Time is a net time, and it's normal to go back and forth between the material and the screen for actual work. But the point is that instead of drawing hundreds of unspecified shapes yourself, the software generates them instantly once you succeeded to create the smooth hull surface. And it can be used in 2D software side without redrawing the line.

I will introduce the software later soon, but unfortunately, it's all subscription software, and it's not cost-effective to have it all on your bed especially from the beginning. However, it is true that owning software has more benefits than cost to increase design freedom.

I expect you to share the resulting drawings with some of your colleagues and distribute the costs.

 

Thanks,

Kiyoo

[PietFriet]

1 hour ago, Kiyoo Iizawa said:

Hi PietFriet,

I have no knowledge of Delftship at all, but I think it can be used if it is software with similar functionality to the 3D graphics software I use. It is a free-form surface creation function by Bezier curve and numerical control function for dimensions and coordinates.

 

Thanks again,

Kiyoo

 

 

Hi Kiyoo,

 

That is indeed the same functionality. Anyone interested to follow the method you describe may also want to look at Delftship as a tool as it is free to use (as long as you don't want to do hydrostatic calculations) and it may have the benefit of framing areas that you indicate in the picture that can't be framed. There are a couple of tutorials on this forum.

 

I am very interested to see what software you use, as they tend to have a fairly steep learning curve. That has been my main issue when picking CAD software (apart from the price).

 

Making a step-by-step guide to get to the laser cutting will definitely be useful, so I'm looking forward to its reveal!

 

Below on example of Delftship

[Kiyoo Iizawa]

PietFriet,

Thank you for your information on Delftship. After finishing my topic, I will study Delftship. If it is possible to use, it is a big benefit in terms of cost. The software I am using will be explained the details later, but it is a software called Shade by Japanese manufacturer.

  Shade 3D Official Website

 

Thanks,

Kiyoo

 

 

[CDR_Ret]

Kiyoo,

 

As others have said, DELFTship's usefulness to the ship modeler (besides being free) is visualizing the 3D hull, then converting that shape to 2D patterns in a 2D software similar to the process you have described above.

 

I don't want to highjack your interesting topic with the details of that process here.

 

What I would like to understand, from simple curiosity, is the process of converting a 2D vector drawing to a laser-cutting pattern. Is that conversion done in the laser control software, or do you have to make the cutting beam allowance in the 2D pattern beforehand? Looking forward to seeing how one does that.

 

Terry

[dvm27]

I know nothing of CAD but I do appreciate the jig/upside down Harold Hahn style method of framing the hull Kiyoo. Fairing those hawse timbers and fore cants is so much easier within this rigid baseboard. I look forward to seeing how the aft timbers come together!

Edited March 4, 2021 by dvm27

[Kiyoo Iizawa]

Thanks for the comments everyone.

 

Hi Terry,

If Delftship or other similar software can be used like my process, you may have increased your choice.

2D software selection as well.

 

First in my case, laser machine can handle Illustrator data without conversion. In addition, by identifying the line color, it can be added the cut priority for instance hole cut first then cut outer shape etc.

Adding the cut beam allowance is done in Illustrator side. It has even offset function and I use this function effectively. These method will also be explained in my introduction.

 

Hi Greg,

My last picture may give you a misunderstanding. My building method is basically upright building with vertical extension to the frame. However, the assembly jig is also accurately cut by laser and can be detached and reassembled quite often. My last picture just show that the bottom jig board has been detached for outside fairing.

The assembly jig has been also improved few times and added the securing and positioning way for the portion which is difficult to assemble. There are for instance, cant frames, hawse timbers, transoms and counter timbers. Next picture shows the securing the counter by adding a positioning piece to the jig.

 

Oh, I have to hurry up more introduction.

 

Thanks,

Kiyoo

 

[Kiyoo Iizawa]

4) These newly generated line shapes can be exported separately as vector data to 2D software such as Illustrator. In case of Illustrator, lines data can be used as it is and no need to modify it at all.

 

5) This allows you to get hundreds of internal and external frame contour information in just a few hours. Of course, it is also possible to generate Hawse timbers and Transoms by creating curved surfaces of bows and sterns.

　This is the biggest and most practical feature of this method. Think about how long it takes to draw exactly this many shapes with conventional way, whether it is a PC or by hand. May be it will take years of time. If you read through this topic, you will be recognized that how this method can create them within a short time.

 

 6) On the other hand, in order to make as parts drawings, the accuracy of the shapes is also required, but this software also have a numerical control function of the shape, and the dimensions and coordinates of the shape are reproduced as accurately as CAD. In addition, this method allows you to pass this information directly to the 2D software for making as more practical drawings. The shapes of following figure were generated or drawn with 3D graphics software, i.e. picture drawing tools, not CAD, but can you imagine that? Dimensions are accurately representing the real dimensions of the scaled model. What is distinctive is that the most of curves here were automatically created by 3D software and they are not drawn one by one. As you can see in the frame diagram in it, the original shape can also be freely edited on the 2D software side.

 

 

To be continued,

Kiyoo

 

[Kiyoo Iizawa]

 Although it is a unique method to use 3D graphics software for generating the complex line shapes of drawings, in addition, 2D graphics software that provides the Bezier curve function is better for ship designing which have many irregular curved shapes.

 The following two figures are various assembly drawings drawn with Illustrator of 2D software, but they are accurate drawings that are completely comparable to CAD. Of course, these are effectively used for measuring and positioning for model assembly.

 

 

 

 

 Recently as another big features, it was found that these data created as drawings can be used for laser cutting. By reflecting the workarounds for the issues found by trial stage into the design drawings, practical application to structural modeling has become possible. As a result, it is possible to process parts without investing the expensive power tools, and it has been possible to reduce the time required for machining revolutionarily. In addition, as you can see in the following picture, the parts for cutting can be laid out much higher density than mechanical machining, so it is possible to efficiently reduce the amount of material used.

Of course, there were some issues to put this method into practical use, but this system has been established by overcoming them and consolidating many features to the maximum.

 I am confidence that this method will make a big contribution especially when beginners challenge scratch building of models. I hope many of you will be interested in this method. Let us take a closer look.

 

 

To be continued,

Kiyoo

 

 

[Kiyoo Iizawa]

2. Configuration of the new method

 This method integrates 3D graphics software, 2D graphics software and laser cutting machine into one workflow to produce accurate design data in a short time. It can also perform the part processing at high speed without compromising the accuracy of the original design data.

 The software used for this method are software "Shade 3D" in Japan for 3D modeling and "Adobe Illustrator" for 2D data compilation. In the past, 2D software has been using "CorelDRAW", and there is also a laser processing machine that can cope with CorelDRAW. However, I have changed to use the Illustrator as a standard because the great advantage of direct data transfer between software. Illustrator also has a wealth of effective operation functions, such as data correction to compensate for the weaknesses of laser cutting, resulting in a shortening of machining data creation time.

 

          Shade                 https://shade3d.jp/en/

                                        3D graphics software in Japan.

                                        English interface is available.

                                        Recommends Standard grade and above.

            Illustrator             https://www.adobe.com/

                                        Famous 2D drawing software in the world.

                                       Language can be switched according to the system language.

 

Even if you are using the CorelDRAW, if you add some conversion processing in CorelDRAW, you will be able to pass it through to the laser cutting machine, so please try it too.

 

3. Features of the new method

 This method has the following features:

1) The 3D software "Shade" allows you to draw smooth and accurate three-dimensional hull shapes from the Body Plan data of the ship you intend to building.

 

2) The hull shape can then be generated the outlines of each frame by slicing the shape (drag a little bit on the any of lateral line) at the desired position. Since the combination of Shade-Illustrator can output these outlines data directly as Illustrator data, redrawing (tracing) of the outline, that was needed at the time of CorelDRAW, become not necessary.

 

Note: In the recent version of CorelDraw, It can become import the Illustrator data. So, once you export data from Shade as Illustrator data, you may be possible to import it into CorelDraw. In my case, sometimes it was unstable but it is meaningful to try.

Also, Shade can export line data with DXF format which is the common for 2D CAD. But unfortunately at the present, it is exported as only folded line and is not curved line. I am expecting further updating of these software.

 

3) Not only the line shapes, since the dimensions and coordinate information can also be shared, it is possible to laid out each part accurately to draw assembly drawings. Furthermore, it is also possible to produce an undrawn part drawings from the assembly drawings. Since all the shape dimensions can be controlled by numerical input, the drawing accuracy is the same as CAD.

 

4) Laser cutting by this data is exactly accurate and fast compared to processing by conventional band saws. Since the parts spacing can be reduced to less than 1mm so material cutting efficiency (yield) is greatly improved. The actual processing can be cut all frame parts (Futtocks) for one ship within only a few hours.

 

5) In recent years, it is possible to rent a laser cutting machines at a DIY workshop and makerspace with a low cost so investing the expensive power tools may not be necessary.

 

To be continued,

Kiyoo 

[CDR_Ret]

Great stuff, Kiyoo!

 

DELFTship exports curves in the DXF format and, as you said, the curves become polylines. The number of line segments depends on the precision level used in the program. I use CorelDraw for the 2D part. It has a feature to convert the corner nodes to smooth nodes, like Bezier curves. The downside is that there are a gazillion nodes, which interferes with creating smooth, fair curves.

 

So far, I'm with you!

 

Terry

[Kiyoo Iizawa]

Terry,

Thank you for checking with Delftship. Shade - DXF export - TurboCAD produces the same result.

I also use CorelDRAW, so I know the characteristics of node (control point) and it is useful.

Does gazillion nodes mean too many nodes? If so, that’s right, DXF format will have much more nodes than I made for some reason, and if you reduce the nodes number without care, you will not be able to restore the original curve when you smooth it out.

This is one of the reasons why CorelDRAW and TurboCAD are not available directly at this time.

We seem to need a little more study around here.

By the way, the number of nodes of the frame curve I created by Shade is 6 to 7 including both line end, and in the case of Illustrator, you can export exactly the same with that number. Of course, there is no need to modify the shape at all.

Next figure shows the one I exported from Shade to Illustrator. Small squares on the line are nodes (anchor point) just for reference.

 

Thanks,

Kiyoo

 

[Kiyoo Iizawa]

4. Making of data using the new method

Laser cutting have a great advantage in accuracy and speed, but on the other hand, it also has some weaknesses that cannot be seen in other cutting methods. This method has also established various workarounds to solve these weaknesses and enable the application of laser cutting techniques for framed structure model building.

Let us look at the characteristics of laser cuts, including the workarounds.

1) Since it is possible to faithfully cut the shape data at a very thin cutting width (0.1 to 0.2 mm) by irradiation of the laser beam, the time of fairing (grinding and sanding) of the model can be greatly shortened. Further, the thickness of the blade (laser beam diameter) also improves the material yield, it is possible to place the parts spacing close together, it is possible to reduce the required material to a maximum of about half as compared to cutting with manual or electric tools.

 

2) Cutting speed is extremely fast, the parts cut of one frame is within a total of about 30 seconds. For instance, in case of 1/64 GRANADO class ship model which cuts nearly 1500 pieces of parts , you can work within a rental time of 5 to 7 hours even if you include the setup time.

 

3) Since laser cutting machine can treat native format data drawn by Adobe Illustrator, there is basically not required to convert and/or recreate the data.

Note : Depending on the laser machine, many formats are also available, .cdr .dxf .pdf and so on.

 

4) The processing function provide options such as cutout, semi-thick cut, and carving, it is possible to distinguish the processing by changing the line weight and color of each line data.

 

5) Since processing is a method of burning through the material by laser, a black burn mark on the cut surface is inevitable (in the case of wood). Parts such as frame, if it is exposed to the model surface, it is necessary to remove the burn marks cleanly. But whole shape of the parts will become reduction in size by sanding burn marks unless expanding the shape. Since Illustrator has a function of offsetting the outline without deforming the whole shape, it is possible to avoid this weakness by correcting the shape using this functionality.

 

6) Because of characteristic nature of laser power to become decrease as proceed forward, the cutting surface is no longer vertical as a result. As a result, glue strength is weakened in such a case of joining the cut parts together because of generating triangular void between parts. As a workaround, cut the shape by flipping one of the adjacent parts, it is possible to align the inclination of the cut surface by applying a technique of joining by flipping it again during assembly and the gluing surface is possible to ensure the parallel. Please refer to section 5 for these specific methods.

 

7) As one of the drawbacks at the present time, there is an issue that wood sheet of fixed size is not easily available in Japan. There were several wood material suppliers in the United States, and it was possible to procure with a fixed size, but recently, some of suppliers began same business also in Japan. The CD data is laid out on a wood sheet size of 500mmx100mm based on this expectation. For other sizes, it is necessary to re-layout according to the wood sheet size. Re-layout is not a difficult task, but you need to operate the software by yourself or please feel free to ask me to lay it out.

 

                                            Laser cut parts, removed from the sheet, sub assembled and roughly faired.

 

To be continued,

Kiyoo

 

[Kiyoo Iizawa]

5. Summary of Drawing Correction for Laser Cutting

This section is an example of drawing correction for laser cutting that I have compiled through the building of prototypes. In order to summarize the drawing correction, I referred to some tips in this Forum etc. 

 

1) Offsetting or Expanding of the parts outline

 Specifically, each futtock in the prototype is offset with 0.3mm margin on Illustrator data.

 Since the outer shape is supposed to be shrunk by approximately 0.1mm by laser, and further margin of 0.2mm is added as sanding fee for removing the burn marks. At fore and aft end frames, much more bevels will be required, but keep in mind that the minimum sanding portion is about 0.2 mm (do not sanding too much). On the other hand, burn mark at the end of each futtock is left so as to it simulates tar caulking of actual ship building when glued together. Above all, this is the adhesive part, so there is also the purpose of not breaking the parallelism of the faces of each other.

In Illustrator, it is easy to add correction in accordance with the site of the shape by function called "Offset Path". Other parts other than the frame are also offset in the same way, but unlike the frame, it is uniformly offset on the entire outline. The adding amount is changed according to the thickness and the shape, it is displayed in the Layout drawings and Offset drawings for each component.

 

Note: I am not sure because not try yet, but if you arrange the offset value according to the situation, may be you can create the data which can also be used for CNC cutting.

 

 

2) Alternating the reverse junction of futtocks

 As mentioned in the previous paragraph, since the cut surface is not at right angles especially in the case of thick wood material, the futtocks of each frame set are joined alternately reversing front and back surface of the part. Therefore some of the futtock are drawn by flipping the outline. Specifically, the second futtock and the third futtock, and part of the cant frame are drawn in flipped condition. These are easily identifiable because it is displayed by also the flipped ID number in the Layout drawings. In the actual assembling and gluing, parts are firstly lay the parts on assembling drawing according to the ID, flipped part again if the ID is reversing then glued them together. This method makes it possible to get much stronger gluing strength and flatting the surface. Since the scarf length of both ends has also been different, there is not a risk of misassembling the top and bottom, but please be careful about the assembly of the frame. The method of the front and back alternating joints are also applied when combining several members in one component such as knee-of-the-head and rudder. They are easily identifiable because of they are flipping ID numbers as well in Layout drawings.

 

 

3) Odd number frames

The odd number frame starting from the first futtock (not from floor timber) is flipped not only intermediate futtocks but also whole frame set of the opposite broadside because lower end of each frame set will be glued together. Therefore, assemble two sets of either port or starboard frame, then flip either one so as to lower end of first futtock is joined firmly together. In the Layout drawings, it is drawn by two sets of futtock ID "s" side (aft frames) and "p" side (fore frames) respectively. It is not a mistake, so do not confused.

 

4) Guide hole

 On the center portion of the frame (portion spanning the keel) and both top end of each top timber (actually at vertical extension part) is provided with 1mm hole for alignment the frames each other for double frame assembly. These holes will also be changed their diameter by laser cutting. Therefore, in the case of center hole of the odd frame, it will be re-drilled to a predetermined diameter (1 mm) with pin vices since it seems that the pore diameter is reduced after gluing both lower ends of first futtock. On the other hand, hole of the even number frame (frame with floor timber) and holes of both the top timber have been previously set the pore size smaller, so that it become a substantially predetermined diameter by laser cutting. During the assembly of the double frame, builder can easily align the inter-positioning by inserting a 1mm brass rod into these three guide holes.

 

5) Laminate structure of beams, etc.

 The deck beam has a blind notch to hold the carling on both sides, such a shape cannot be easily produced by laser cutting. Therefore, one beam has consisted of a structure of three layers. They are the center portion without the notch and both sides with the thickness of notch depth. Further, guide holes of the same idea as the section 4) are provided on both ends. This holes are become invisible by the knee after assembly. This lamination method is also applied to the assembly of the bitts and the catheads which have hollow holes their inside.

   Lamination idea is based on Bob Hunt's Kingfisher kit.

 

 

6) Fitting with assembly jigs

As described above, the portions that can be dealt with by the joints between the parts and the like are being corrected, but some other parts are not. To ensure the assembly accuracy, portion where it is tight need to be sanded a little bit.

 

To be continued,

Kiyoo

 

 

[PietFriet]

Some very useful tips!

[Kiyoo Iizawa]

Thanks PietFriet,

Because the benefits of laser cutting are highly efficient for scratch building, I thought that to solve some issues of laser cutting will be extremely useful. So while verifying this method with several colleagues of the association, we recognized the issues and taken countermeasures to them. I am still on the way of improving/updating this method.

 

Kiyoo

 

[Kiyoo Iizawa]

6. Deployment to assembly jigs

 The application of laser cutting techniques can be applied not only to accurate the parts, but also to the creation of jigs that ensures assembly accuracy during assembly. In the assembly of the framed structure model, it is necessary to assemble a large number of parts with accurate alignment, but it was also found that the jig plate for positioning which becomes the guide can be easily fabricated with laser cut using the several assembly drawings data.

It is possible to design the jig incorporate with the necessary ideas such as reproducing the notch shape to accurately holding the frame top, reproduction of the angle of the cant frame, the addition of various reference lines and so on. And because they can be easily applied to the jig configuration, the assembly of the hull can be made revolutionarily easier.

 After several attempts, the latest design is applying the following features:

1) Cutout of the outer periphery of the jig plate

In the beginning, the outer periphery of wood sheet was used as it is. But since there is a possibility that the center position misaligns at the time of setting of wood sheet to the machine, it was finally decided to cut out the outer peripheral portion with a certain dimensions. By this, relation between outer frame and center line of the jig plates is always kept. Also, since it can be possible to accurately align the relative position of the stanchion and the fixing holes, it become easy to assemble the jig.

 

2) Preparation of the stanchions

 In the beginning, it was assumed that the fixing stanchion of the upper and lower jig plate will be prepared by the builder oneself, and only the drilling position for fixing was displayed on design drawings. However, since the jig accuracy may collapse by the stanchion length and the accuracy of drilling hole, it was decided to prepare these stanchions as one of the elements of the cutting data. In addition, these were made to be able to put out the position accuracy even if only by fitting each other.

 At our trial stage, only by inserting the six stanchions in each position, the relative position of the upper and lower plate can be secured without gluing, it seems enough for the assembly of the frame. If you are concerned about the looseness, it becomes more stable if you fix the front and rear of the jig simply with a rubber band or a string. I am only using masking tape to temporarily fix the stanchion and the board. The reason for a recommend that not fixing the stanchion in this way is to avoid that some of the stanchions disturbs the action at the time of such measurement and processing of the hull outer surface. Also, it enables to remove hull from jig for easier fairing and sanding of the entire hull.

 

3) Clarification of the reference position

 The hull design has taken the method of dividing the midship position back and forth as zero position based on the contemporary design standards of the ship, but it was found that it is difficult to measure in actual assembly of the model. Therefore the reference position on the assembly was changed to start from the hull ends, it was to display the representative dimensions from there on the jig plate by setting the zero position at both ends so that accurate measurement can be made from either end.

 The specific zero position is the fore top end of the stem and the aft top end of the sternpost. The hull (keel) support on front and rear the jig is also supported in this position.

 

4) Proper reinforcement and measurement guide

 Although concept of the jig is well providing sufficient usage as mentioned above, it is recommended to attach a foot of aluminum channel as reinforcement. There is also an option to provide rails to guide the instrument for measuring the inside of the hull from the top.

 

 In the process of prototype verification, this jig demonstrated great power in positioning the parts during assembly and in various measurements.

 

 

To be continued,

Kiyoo

 

[Thistle17]

Klyoo I have explored this arena  (bringing today's technology to this pursuit, I worked with a colleague to convert laser DXF files to CNC G code, it was a real eye opener for me) but I pale in your light and work! Just outstanding. I await your completed treatment of the process but follow your good works.

Jooe

[Kiyoo Iizawa]

Hi Jooe, thank you for your comment.

I also have been encouraged of the CNC by Bob Hunt’s Kingfisher kit. But at that time I never thought that I can personally handle either CNC or laser cut.  But recently, I found that laser cutting fills my all requirement which is that I can prepare the data using my existing properties and also can operate the machine by myself. That is the reason so far, I selected laser cut rather than CNC. I think CNC may also become familiar soon to individuals same as laser cut.

I propose the way of open public of my procedure manual in next post.

 

Kiyoo

 

[Thistle17]

Kiyoo my experience with the results of the conversion (DXF to G code) taught me some lessons. For one, inside corners will always be rounded unlike laser processing. For outside corners the cutter has to go by the corner and return at the corner to have it come out square. As with laser machining there is always the feeds and speeds issue but the hardest lesson was that laser instructions seem to be much more forgiving in terms of path travel (we found arcs that were not continuous in the laser file that would not work in the CNC mode). Discontinuities in lines, arcs have to be "smoothed", nodes must be precise and so on. All in all i got my parts (for bulkheads and strongback) and they came out well. I believe you are absolutely correct that laser machining is the way to go. It would be the premier way if one could find a solution to char and the "slope" of the cut.

Joe

Edited March 10, 2021 by Thistle17

[Kiyoo Iizawa]

Joe,

Thank you for the comparison between CNC and laser. They are each have the advantages and the disadvantages. But any of the way, I am sure they become strong aid to make the parts for scratch building, especially the case to cut the uneven curved shape.

There are not many restrictions on the feeds and speeds in laser cutting. That may be due to the extremely small thickness of the blade (the diameter of the laser). And for now, Illustrator is responding well to the changes and corrections the data for cutting.

Yes, “char and the slope of the cut” is a relatively bigger issues in laser cutting so far. Although I provide some countermeasure for them, I appreciate if anyone find more practical way to solve.

 

 

Everyone,

My brief introduction will be closed soon. So, I am thinking now to freely provide the procedure manual of my method to those who wish to learn and use my method.

Does anyone can advise the data storage method so that only the MSW member can access to there.

 

Kiyoo

 

[druxey]

Clever use of lamination on the deck beams and compensating for angle of laser cut!

Edited March 10, 2021 by druxey