3D Modelling Software Recommendations

There is also Autodesk 123D Design

Autodesk 123D Design

which supports 3D printing. Ben Heck has used it on his show a few times.

Some of the quotes for the project I was working on appeared to be quite high as well however I put that down to it being a slow process and each print job tying up a machine for long periods of time.

Also perhaps need to differentiate between some of the different technologies here though. A powder bed deposition machine, or resin stereolithograpy machine is likely to cost a bit more to purchase than a fused deposition modelling machine.

However I made similar comments to the project requester that it would likely be more cost effective to get the likes of a Tevo Black Widow kit (the only sub £1k printer kit which I could find at the time with a large enough bed) and do it in-house as it would likely pay for itself within the timescale of the first project, and then be a useful resource to have around to enable future projects or provide as a general low cost in-house service. There are some hidden costs however such as space to accommodate such a large printer and perhaps installation of ventilation and space heating for working with some plastics like ABS, additional software and the time taken to assemble it and get it to a stage whereby everything starts to work.

There are also some other considerations - my design could have been part laser cut/engraved and part 3D printed on a smaller printer however the requester in this case was keen for it to be 3D printed in two halves after seeing the first 3D model.

HellO Dave

First of all you should never include the startup costs (those you mention like the site preparation etc.) as these increase senseless the first project production. And it is anyway a wrong evaluation of the costs. You should plan how and for how much you will use the machine. For example you are right thinking to a tool for low cost in-house third party production. At this point these costs become a number: the break even point. I mean how many projects or pieces you should produce before the machine cost and accessory is totally absorbed. I think that anyway it is not so high and probably you will cover the investment with the first two - three projects.

Second - I think that you should not include the time for initial settings that you mention. It should be excluded at all. Else if you want convert it in a cost, also calculate the delay time you need doing every part to a service.

Despite I remain of the opinion that the 3D print HUBS are a great idea these are perfect for small productions but not for prototyping: the concept is that if you want to make a project it is mandatory that you own the tools needed to create the project. As a photographer own a digital camera and a computer for his creations (and when I started in photography we was having the darkroom absolutely more expansive than a digital system), as a woodworker has a router to make his own stuff and an electronic engineer has its own soldering station why not a project that involve material machining can't follow the same path ?

I have exaggerated just to make an example that in my opinion making something means making something. Else it is designing something then sending somewhere to ask others to make it.

Enrico

Really nice but I think we are still missing a few dimensions to work with on the 3D printer here 

• The top diagonal face - both end points
• The lower diagonal face - the end point in the centre
• The thickness of the base is unclear as well - looks like it could be 2mm but ambiguous

Dave,

checking with attention, you can see that all the dimensions are shown directly or indirectly. The only mistake is the thickness of the base while all the other information if not directly quoted can be deducted. This is a technique used in all the quoted designs to avoid too many quotes. Personally I find this method of the indirect quoting a bit complex to read but I am aware that this keep the design clean.

Enrico

Enrico,

Struggling with points 1, 2 & 3 even with attention.

Point 1 - is 8 from the top edge but I don't see a measurement from the left or right edge. Looks to be less than 6 from the right edge though.

Point 2 - there is no centre for the radius of the fillet to get a tangent for the edge of the diagonal face.

Point 3 - is 31 from the top edge but I don't see a measurement from either the left or right edge. Looks to be less than 23 and greater than 15 from the right edge though.

Hello Dave,

This is an almost complex piece and quotes are not easy to deduct.

1. Here you have a 8x8 square (view from top) and inside a 6x6 square. So the internal straight line connect the two sides of the square intersecting at 6 and 6. CAD usually gives this option to close with a straight line a surface (that then will be extruded) deciding the intersection points.
2. These radius didn't need center. The reason is that these are not circles but arcs. Usually in CAD you should have several options to design arcs, in this case the ideal option in my opinion is arc by radius and two point. You set the first and second edge (that is exactly 90 degrees of an arc) and set the radius, then the CAD add the needed calculations.
3. If you refer in this case to the internal straight line, the procedure is the same as in point 1. If you refer to potentially missing measures, the approach is the same: the internal part is 31  over a total length of 46 by one side and some calculation on the other side.

The parts that seems not correct are automatically generated as the arc is fixed and the total length is shown on the other side.

The issue in this design is that there are some wrong proportions respect the sizes to if you make a real object with these measures maybe you have some surprises. Remain the fact that designing with a CAD program it is sure extremely easier to generate with less measures but using relative reference points (e.g. intersections. Take in account that it is best practice with this kind of objects to create easy sub objects then joining them and applying boolean operations like element subtraction.

BTW maybe I am not so clear due my language difficulties.

Enrico

Hi Dave!

You could be right, its a limitation of doing it manually, I could miss bits.

Whereas a 3D modelling system would not construct the shapes unless all

parameters were present, and then they can be used for generating the documentation (I'm guessing).

Its a bit messy labelling all on a single isometric to be honest. But its the view most people recognise (probably orthographic projections are less familiar unless people are from an engineering background).

beacon_dave is right about all 3 points. They are ambiguous.

Hi!

I don't doubt there could be missing measurements, (by the way this is a duct part, we expect duct area to be approximately consistent through the part).

Actually I believe we could fix it with a single value (e.g. x degrees) and either text, or a center line. I'm not 100% sure this is valid on an isometric, but for an orthographic it would be.

For example:

The center line or text would indicate that duct property we desire, i.e. parallel lines inside.

We already know the duct inside is 31-1.5 = 29.5mm.  And we know where the lower-rightmost leg of the duct is placed, because it is marked as 2mm. So this would result in all measurements being defined.

The thickness of the part is not implied, it is given, you can see the 12mm measurement marked at the right side of the diagram, and 10mm marked on the left side of the diagram.

I agree with Enrico, I don't believe any more is needed on the radii. Ordinarily that would 'naturally' occur if your tooling was of the same radius. I'm guessing when you do that in a CAD package, it would internally compute it the same way.