Former Member | 01/08/2019 10:58:27 |
1329 forum posts | [This posting has been removed] |
FMES | 01/08/2019 11:19:50 |
608 forum posts 2 photos | Hi Bill, Its so that the dimensions can be entered directly into the computerised cutting machine whithout the company having to do any design work. Only problem is, if there is a mistake its the CAD artists fault and not the cutters. Regards
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ega | 01/08/2019 11:27:13 |
2805 forum posts 219 photos | Is there some way a laser cutter can do a dummy run to check? |
Cornish Jack | 01/08/2019 11:28:01 |
1228 forum posts 172 photos | Re. laser cutting, yesterday I received a completed order from 'Original Forgery Ltd.' . It was just a simple set of decorative windvane direction letters but the quality was outstanding and the delivery lightning fast. No connection etc. but they will certainly be first port of call for any further work. rgds Bill |
duncan webster | 01/08/2019 12:20:24 |
5307 forum posts 83 photos | Posted by 34046 on 01/08/2019 10:58:27:
Asked for some plates from Model Eng Laser and was told drawing no good it had to be in CAD. Googled Cad so realise what it is. Interested to know, in simple terms, why they insisted on CAD I ask as computers are still a mystery to me Thanks Bill Laser cutting machine is computer controlled, so it needs CAD drawing. If you send a pencil drawing someone will have to convert it to CAD which will cost as much as doing the actual cutting, if not more, and introduces the possibility of the CAD man getting it wrong |
Former Member | 01/08/2019 12:31:29 |
1329 forum posts | [This posting has been removed] |
Dave Smith 14 | 01/08/2019 13:29:06 |
222 forum posts 48 photos | Bill Email me your drawing and I will produce you the dxf file which Malcomn needs. I will message you my email address. Regards Dave |
Paul Lousick | 01/08/2019 13:34:32 |
2276 forum posts 801 photos | Is there some way a laser cutter can do a dummy run to check? You would have to cut the plate to be able to check it. The laser profile cutter could trace out the path it would take to cut the plates without cutting but it would be imposible to measure. In the days prior to laser cutting and CAD systems, steel plate was cut with machine with an oxy torch which traced the outline of a hand drawn template, drawn at a scale of 1:1. The finished size of the cut plates depended on how accurate a drafter could draw the profile with an ink pen, usually on plastic film which did not expand or contract like paper as it absorbed moisture. Steel plates could be cut with a 1mm - 2mm accuracy. The advantages of doing everything in CAD (Computer Aided Design). is that the models and drawings can be drawn to a much greater accuracy. (eg. 0.00000001mm). Mating parts are assembled in the computer drawing and it is here that dimensional checks are made. Some CAD systems can automatically check for interference problems with mating parts. Much cheaper and easier to fix before it is cut from steel. Most oxy, laser, water jet cutters use a computer program to cut the profile and if a CAD file is not supplied then someone at the cutting company has to make one. Some profile cutting machines have built in programs which can cut basic shapes without a CAD file but are limited to rectangles, circles, etc. I had laser cut spokes made for the steel wheels on my traction engine and they were cut to within 0.2mm accuracy. Paul. Edited By Paul Lousick on 01/08/2019 13:36:01 |
Ben Charlton | 01/08/2019 13:35:22 |
14 forum posts 1 photos | Bill, Depending on how complex the plates are I could potentially sketch them up in CAD for you over a lunch break or 2, Obviously if they're fully detailed side plates for a 7 1/4" mainline engine I might shy away!
Regards, Ben
Edit: I see I've already been beaten to it! Edited By Ben Charlton on 01/08/2019 13:36:33 |
Former Member | 01/08/2019 13:47:58 |
1329 forum posts | [This posting has been removed] |
David Jupp | 01/08/2019 14:43:28 |
978 forum posts 26 photos | Posted by ega on 01/08/2019 11:27:13:
Is there some way a laser cutter can do a dummy run to check? Kind of; the g-code prepared to drive the machine can be plotted in a simulation program (many cnc controllers will plot the toolpath on screen anyway before starting, which can give a quick check). If using a simulator program, it has to be set up to mimic the controller being used (they vary in the fine detail). And of course an on-screen 'check' is only useful if the person looking at the screen knows what it should look like... |
ega | 01/08/2019 14:45:01 |
2805 forum posts 219 photos | Paul Lousick: Thank you for the explanation. I suppose I had in mind that it might be possible (if not economic) to run the laser using some suitable cheap material to produce a result which could be checked by the customer; all being well, the real job could then proceed. |
Ian McVickers | 01/08/2019 22:14:32 |
261 forum posts 117 photos | The cad file, either dxf or dwg, will be run through a post processor to convert it to a cnc file, g code or essi for example, which the machine controller will understand. The post processor will also add the necessary auxiliary function codes for beam on, beam off, kerf, speed etc. |
Paul Lousick | 02/08/2019 00:23:27 |
2276 forum posts 801 photos | Hi ega, Laser cutting services use expensive machines and their charge out rate has to cover the cost of labour and business overheads and to cut a sample would be expensive. It's not just for cost of the material used. Not many firms have a service where you could wait at the counter for a job to be done. Instead it would be scheduled into their work program and made at a later time after placing an order. Then you would have to come in and check the job and if OK, re-scheduled again for the final cutting. It is a different matter though, if you need hundreds of the same part and the cost of a sample part is justified. Paul. |
Neil Wyatt | 02/08/2019 10:01:08 |
![]() 19226 forum posts 749 photos 86 articles | Posted by ega on 01/08/2019 14:45:01:
I suppose I had in mind that it might be possible (if not economic) to run the laser using some suitable cheap material to produce a result which could be checked by the customer; all being well, the real job could then proceed. Usually the material is one of the cheapest elements of the process, especially if you are using steel. Also bear in mind that if they used card, they would probably have to cut it on another machine as I doubt you could 'tune' a steel cutting laser low enough for it! Neil |
ega | 02/08/2019 11:31:40 |
2805 forum posts 219 photos | Thanks for the further enlightenment. My only experience of this sort of thing was when a friend produced some large artworks in steel and roped me in to help him erect them. I don't remember the process - they might have been flame rather than laser-cut - but I do recall acquiring some of the circular offcuts.
Edited By ega on 02/08/2019 11:33:01 |
Ian P | 02/08/2019 13:41:13 |
![]() 2747 forum posts 123 photos | Posted by ega on 01/08/2019 14:45:01:
Paul Lousick: Thank you for the explanation. I suppose I had in mind that it might be possible (if not economic) to run the laser using some suitable cheap material to produce a result which could be checked by the customer; all being well, the real job could then proceed. I have had many parts made by laser and waterjet cutting and every one was correct and exactly to the drawing I provided (a DXF file). The only ones that were not suitable for use were ones that I had made a mistake on the drawing. Basically there is no need to make a sample or test cut because the part will what you ordered. Any checking needs to be done before the part is cut. Ian P |
John McNamara | 02/08/2019 13:45:55 |
![]() 1377 forum posts 133 photos | Hi Bill Regards |
Dave Smith 14 | 02/08/2019 15:48:48 |
222 forum posts 48 photos | John I am already doing the job for Bill, in fact it is finished I just need to send the dxf and pdf for Bill to check he is happy with it. Dave |
Former Member | 02/08/2019 19:56:27 |
1329 forum posts | [This posting has been removed] |
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