Member postings for John McNamara

Gee Dave
You Mentioned, "(I used to do precision high speed large volume optical metrology at a previous job)".

Are you able to say how?

Regards
J

Re the image on the link in peak4's post
https://www.printables.com/model/58546-dan-gelbart-laser-center

I like the spherical arrangement of the laser mount adjustments.
adjustment in two planes with two lock screws only.
That is a nice piece of design and part minimisation.

Not easy to machine but easy to 3D Print.

Hi

Something to consider is a manual method of operating the tables should a power failure occur.

In The UK there is a voluntary engineering group called Resmag **LINK**

I wonder if a similar organisation exists in the US, If you don't mind me asking what state do you live in? I can think of a few UTuber's that might take this project on.

Lets get this project on the way ASAP.

Maybe you could use a standard SS union coupling, Get one oversized and sleeve the the inside with flanged Teflon inserts so no chemical touches the SS coupling bores?

**LINK**

Edited By John McNamara on 10/08/2023 04:17:27

Nice find Michael

We used to distribute their textiles in Australia
A great company to work with.

Sikaflex for sure it also sticks very well if the surface is clean, contact the local supplier. Never silicone, it is not nearly as durable, and forget expanding foam for detail work.

For a nice job mask both sides with tape. apply the Sikaflex to the slot then spray on a little soapy water (if needed) then smooth with a wet finger. finally remove the masking tape straight away while the Sikaflex is still wet. Finally! try not to improve and fiddle with it unless really necessary.

That's how the professional Caulkers do it.  

Oh! Sikaflex is available in colours.

Edited By John McNamara on 12/07/2023 08:48:12

As I suspected composite fibre pressure vessels do not prove reliable when subjected to external rather than internal pressure, delamination is likely to occur.
The video link below is worth study and thought.

**LINK**

Regards
John

Curtis and his partner are amazing... Big Iron Big chips and no advertising, Oh and a big dog too.
He has more You Tube subscribers than Abom now.

A sad day, a loss of 5 people affecting many families and friends.

From what I have read a large percentage of the craft was carbon fibre, made into a pressure vessel, in this case the hydraulic force applied to the vessel was on the outside skin. Does this mean the strands of carbon fibre within the epoxy binder forming the walls of the vessel are in Compression?

Most carbon fibre pressure vessels used today contain pressure on the inside of the vessel, the strands of carbon fibre within the epoxy binder forming the walls of the vessel are in tension, usually referred to as the hoop stress.

This makes me wonder if carbon fibre in an epoxy binder making a composite material has superior mechanical properties to say steel or titanium in compression? Epoxy being a plastic will creep under a moderate load if used alone. So what happens to a composite material made from carbon fibre and epoxy when the force is on the outside of the walls. The hoop stress is reversed.

I can only wonder what material physics are at play? if the epoxy binder were to creep as I think it will, the carbon fibre layup (There will be many layers of strands or cloth) might even be subjected to buckling, a common failure mode for columns. Or delaminating. I also assume that the pressure vessel is not completely symmetrical no doubt there will stress concentrations in particular areas.

Maybe a structural engineer in the forum could put my (amateur analysis) right.

Ribbit
https://www.pond5.com/sound-effects/item/125216646-frog-ribbit

Edited By John McNamara on 21/06/2023 04:26:48

Frogs use them!

rivit rivit....rivit

Edited By John McNamara on 20/06/2023 14:26:04

A few years ago...
I started writing essays with a fountain pen. Now I use a computer that even corrects my not so great spelling..
Seeking knowledge was at the Library. I can still remember trawling through the index cards only to find the book was on loan and I had to wait. Now I can get a general answer in a few minutes, empowering my research along the way.

There is so much to do! With this enhanced ability comes the responsibility to make all things a little better in some way to and improve the body of work that represents civilisation.

It is good to look back only to the extent it confirms a path to your future. To me living in the here and now in the knowledge age is wonderful.

Its a bevel gear drive.
if it is loose turn away a small part of the narrow end of the gear and possibly the pin, It will engage better.

Yes it does look promising. If only it included CAM apart from 3d printing many people have small routers and mills.
Sadly most low cost or free roads lead to Fusion 360 for that at the moment, a real pity.

Actually CHKDSK

https://www.google.com/search?q=chkdsk&oq=chkdsk&aqs=chrome..69i57.3530j0j15&sourceid=chrome&ie=UTF-8

If extruding or sweeping a line Instead of abrupt 90 degree changes in the line try filleting the bend first, then extruding the pipe form over that. In real life pipework there is always a radius, the canter point is normally outside the pipe itself in free space. This will give a more natural form of bend.

The nickel plating is really nice, so are the collets, depthing tool, staking tool and other accessories in nice cases.
Its truly wonderful. Could it be a Lorch?

**LINK**

Agree Jason
As I said the free version has restricted functionality so we will have to pay for the standard version. I don't want to get pushed further onto Autodesk's gravy train. Solid edge will help avoid that. The new machine will be used by me and my son. we are researching some ideas that have so far only existed on the disk drive and on paper. We don't plan to take in job shop work. He is still at University. We comply with the incensing terms for Solid edge at least for a while. While it is easy to hoist the jolly rodger we prefer to keep things shipshape and above board.

Oh I have found that as well as the many other formats Autocad and Solid edge can export 3d step files. These can be imported into the free version of fusion 360 without difficulty. The free version has very limited import capability.

Open source FEA tool
An engineer friend uses and highly recommends this tool, I downloaded and installed it, no problem, I have not tried it yet but it looks impressive. It is being actively updated, important for open source software.
https://prepomax.fs.um.si/

Edited By John McNamara on 12/04/2023 01:00:58

Edited By John McNamara on 12/04/2023 01:21:56

I just upgraded last years Solid edge to the current 2023 version. You have to delete the old version first.
As I have stated previously I have done all of my 3D Cad design using Autocad .dwg format Any 3D drawing I have posted on this site was drawn with Autocad. Having used it from version one I find it easy to use. it is very easy for me to do 3D design sketches due to the ease of joining and manipulating local within the current drawing geometry and "Xref" parts, components shown in the current drawing but in a separate file. I have a perpetual 2021 licence that cannot be updated unless I move to subscription at a cost of double the old maintenance fee. No Way!

Fusion 360 cad is not my favourite design application for several reasons:
I don't like cloud storage. It bogs down from time to time, Although it supports separate components they are all in the one file. Import export is severely restricted to only a couple of formats. The free version is crippled in various ways. and even the Standard paid version at about 600 AUD dollars a year has missing bits that you can only access with the Advanced versions, each costing around 1600 AUD dollars a year. Oh and if you want simulation that's extra you have to buy cloud credits to use it more thousands per year. I guess you could say I am not a fan.

Solid edge Community edition 2023 (Siemens states the licence will last for three years from the date installed) I Guess they will honer the contract. Well I hope so.
This is a powerful 3D design tool, that ticks many of the boxes for me. It is not cloud based, the application and design files are stored on my computer. There are part files and assembly files separate on disk, that works well for me I have a library of previously drawn parts. Oh and you can drag and drop files from other applications into the currently open drawing. Including DWG files. The translation is pretty good Most of the time 100% and the dragged in file can be immediately edited. It can export many formats. Finite element analysis is built in no charges to run it. The same applies to generative design. Basic engineering elements are available. Gears Shafts racks etc. You can specify them by size and tooth count, or input the torque, speed, and materials etc and the tool will size a gear pair for you. Its is a very comprehensive design tool. It supports 3D printers but not CAM.

Solid edge Community edition 2023 does not have any CAM functionality. It is a available at a cost of several thousand dollars. Really the only downside, For manual machinists it will not matter.

I intend to learn Solid Edge Having worked on it over the past 2 weeks I realise that it will take some time to be as fluent as I am with Autocad. I think the effort will be worth it.

So I am back to Fusion for Cam, Yes at the moment the best deal on offer. The crippled free version will do 3D cam without rapid moves and some other machining strategies. If you have a fast CNC machine you will have to pay more. The standard version as stated previously approx 600 AUD dollars per year removes some of the limitations. As expected if you have 5 Axis you need the more advanced version. Isn't modern marketing great Hmmm

So where from here? I have a new CNC machine on order and will drive it with Fusion for the time being. Hopefully the free version, unless they play more tricks to make people pay up for at least the standard version. No I am not a fan!

One possibility is FreeCad, It does include CAM, I have been watching it for a while now I don't think its quite ready yet and being open source the development is slow.

Solid Works also have an almost free version, Is it 100 dollars a year? I believe there is some sort of cam attached?
I believe It is web based so I passed over it.

You never know something else might pop up!

Edited By John McNamara on 11/04/2023 15:18:21