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I use Contiboard with double sided tape on my CNC mill which I suspect might be the same melamine product that Giles uses. :-) It is remarkably accurate and I can get the work surface on it accurate to within a thou quite easily. However, I did read somewhere that melamine can take the edge off milling cutters so I tend to avoid cutting into it if I can. I'm not sure if the warning is for HSS cutters and carbide cutters. I use carbide cutters nearly all the time and I try to avoid digging into the Contiboard if I can just in case. :-) I also use double sided tape and the few thou thickness of the tape allows the cutter to cut through the material without hitting the Contiboard. I also use 12mm MDF as a spoil board where I have to use other clamping methods to hold the material, either using clamps from the "T" slots in the table or wood screws into the MDF itself. It works well and is almost as dimensionally accurate as the Contiboard. It is also handy for building up supports for items which can't be clamped to a flat table and you can use the CNC mill to cut the parts for the mounts so that the edges and angles can be accurate. Here's a picture of a typical flat setup clamping on MDF The part being milled was the end of a JLTRT 7mm resin coach kit and the alloy angle (B&Q) located the part and spare venetian blind strip clamped it down, using screws into the MDF. At this point I was checking the setup of the part before milling. In the next picture, a special mount was made from MDF This was to hold a roof for the same resin coach kit on the fourth axis so that I could mill a recess on the roof ends. At this point I'm plotting the curve of the roof before generating a GCode file for cutting. All the MDF parts were machined on the mill to be sure of nice, accurate angles. :-) Jim.

I came across a peculiar fault yesterday. I had been doing a lot of brick etching and cutting out of building sides for several days and I had left the machine cutting out a brick etched side. When I ventured back to see how it was getting on, the laser fence was lying on the base and the head was still going through the motions with the laser off. I looked at the laser hood and there was a large build-up of fused rubbish on the inside front edge and it was possible that this had eventually fouled on the material and forced the hood off the laser head. The build-up extended to where the laser beam was so there might have been a small fireworks display at some point. :-) Unfortunately, I cleaned out the build-up without taking a picture of it. But I took the head off this morning to find a a sort of pebble dashed lens. :-) This actually cleaned off easily with a firm bristle paint brush and no harm seems to have been done to the lens or the laser head. You might also note the brass cheese head screw. It is 8BA into a drilled and tapped hole in the laser head extrusion. This now locks the diode assembly in place instead of the grub screw. I have removed the grub screw and the head can now be removed easily after disconnecting the plugs. This means that I can clean the lens without removing the lens - requiring re-focussing. Replacing the head can be a bit of a fiddle since you have to depress the spring button which gives the necessary friction to hold the head in place. This picture shows the relationship of the screw with the original grub screw hole. I'm still working with the original lens and I'm cutting through 1.5mm MDF (Maple Street) at 10mm/sec, 90% power and five passes. With my glass base I can see that the cut is probably complete in four passes, but the extra pass allows for a bit of lens inefficiency with accumulated soot. I've had one or two cases where the cut through has not been complete for whatever reason and it is pretty well impossible to get a side with a lot of brick edge interlock out of the material without damage. I might go back and give the G7 lens another try to see what improvement I get this time round. Jim.

Paul, Try loosening off the hex grub screw which locks the diode assembly in place and pull the diode assembly down about 2mm so that it projects out of the alloy body of the head. This alteration might adjust the focussing of the lens to allow you to get the best position. With its original lens, best focus on my Emblaser was achieved with barely half a thread engaged and the lens tended to wiggle about as well. At the moment my diode assembly protrudes about 3mm and my original lens is held by more than one thread. I haven't investigated how the actual diode is held in the tubular holder. It could be that there is bit of a manufacturing variation on the back focus distance with the standard lens and your diode is right on the end of (or just past) the permissible position. Jim. [Edit] I think I remember that I had to carve a bit of clearance on the finning inside the hood to clear the protruding diode assembly.

Result. :-) :-) Jim.

Paul, Looks like the FFC could be the culprit. With modern semi-conductor equipment which has pretty high reliability, the usual causes of intermittent problems are cables or connectors. There's also the short cable from the diode to the connector on the laser head which might be worth looking at as well. If you think it might be your FFC cable, I've got a spare here which I could send to you to try out. It's my original cable which I replaced with one which Dominic sent me to see if my fault disappeared, which it didn't, so I assume the cable is OK. I couldn't find a local supplier of a replacement cable. The ones available are too short and I suspect that the people at Emblaser get ones made specially for the machine. I have also noted comments in the support forums about checking for brown markings on the FFC cable which would be indicators of arcing where connections were poor or conductors were broken. Jim.

Paul, I got the file and had a quick look at it and it looks fine. I thought it might have somehow got multiple laser ON/OFF commands but there was just one "ON" (M3 S255 (100%)) at the start of the file and two M5s (OFF) at the end. So the laser should come on continuously for the whole of the cut of the circle. One thing I did notice is that the file consists of a series of short chords to draw the circle using the G1 command, and there are 843 lines in the file. This is the way that your machine controller actually generates a curved path but the GCode to drive it is usually a lot more efficient and uses the G2 or G3 codes to describe the circle for the controller. I drew the same circle in Cut2D and generated a file and that used the G2 code and contained only 15 lines. :-) It might be worth drawing the circle in Cut2D and see if that works any differently when cutting the circle in the Emblaser. You can view .nc files in a simple word processor like Notepad or Wordpad - they are basic text files - and it gives you a chance to check the line count of the files and whether G1 codes (lots of lines) or G2 codes (much fewer lines) have been used. If it cuts OK with the G2 code then there might be a wee bug in the Emblaser firmware which doesn't like circles described as very short chords in GCode. But I suspect that your fault will be elsewhere since a lot of graphics programs use short chords to describe circles and I think such a fault would have been reported already. Another possibility might be a poor contact with the flexible cable which gives a poor connection when the laser head is in a certain position. If you cut the circle and the gap is still there, try cutting again and persuading the cable to adopt a different loop and see if the fault is still there. Jim.

Paul, Is it possible to see the .nc file which is used when you get the problems cutting a circle. When it keeps happening in the same place after you changing parameters, there has to be a constant somewhere and that could be in the Gcode - for whatever reason might cause that. I've also been working with the upgraded Cut2D laser V9 and it seems to work well although it refused to produce a tool path for a brick etch which had worked OK in earlier versions. It looks as though they might have put a bit more error checking in their code generation but with thousands of bricks in the etch, I didn't feel like checking every one to find out which one might be causing the problem. :-) The main improvements in Cut2D V9 Laser would appear to be in the drawing facilities - much the same as in the CNC Desktop version. There is a video about the new Cut2D Desktop CNC version which shows the added drawing facilities which look to be the same in the new laser version. https://www.youtube.com/watch?v=hMFClBMD2x8 But they have tightened up the generation of tool paths and they are now quite tightly integrated with the tool database. The kerf width setting has disappeared from the tool path dialogue box and you can only set it in the tool database settings. I found the same as you with the use of VTransfer and sending direct to the cutter, which I prefer as well. One thing I noted was that the basic preferences for VTransfer for A4 set the X width to 305 when it should be 300. So if your cutter goes to an X setting between 0 and 4, it hits the left hand end X end stop with a bit of a bang. :-( It was the same in the previous version of VTransfer. The X and Y defaults can be reset in "File/Settings". On your cutting through problems, I've been having similar concerns but nowhere near as problematic as you. I've now got my 4W cutter cutting cleanly through 1.5mm MDF at 10mm/sec and 90% power with four passes but it was having difficulties cutting cleanly at 16mm/sec at 90% and nine or ten passes. Pro rata, with the speed difference, the 16mm/sec cuts should have been achieved with six or seven passes. I am suspecting some form of charring which is preventing clean cutting at the higher speeds. So you might try dropping you cutting speed and see if your situation improves. I'm using the MDF I get from Maple Street and I was thinking about trying some from another source to see if the problem is repeatable. For the above cuts I'm back to using the original lens since both of the higher efficiency lenses I got don't seem to provide much improvement and the original lens gives me a smaller kerf width. Jim.

I was wondering if V9 would be appearing for Cut2D laser. I upgraded my Cut2D Desktop for my CNC machine to V9 a few months ago. I'll go and have a look at upgrading since I'm used to working with Vectric Cut2D and would prefer to stay with Cut2D laser if the V9 upgrade sorts out some of the existing bugs. Jim.

Nick, Did you try earlier versions of DXF if your program which produces the DXF can do that? I tend to use the R12 version of DXF since most programs seem happy with it and my version of AutoCAD LT and Draftsight will export R12 DXF. I think a lot of programs have problems trying to keep up with the latest version of DXF from AutoCAD. Jim.

Giles, Thanks for that. That gives me parameters to measure against. I've not quite got the problem that others have as noted on the current thread on the Darkly Support forum but I do suffer from variation in performance which can be very annoying. I recut a set of sides for a building with a lot of brick interlace at the corners using the previously used settings, only to find that the laser had not cut through sufficiently to allow the pieces to be removed from the sheet without damage. So everything was a write-off and I found that I needed another three passes (nine instead of six) to now get a clean cutout. Jim.

Giles, What speeds of cut do you use in these cases? Jim.

Well, I got things set up today and did some test cuts on the ply from Kitronic. With the 0.8mm ply, a 4W diode at 90% power and the original lens, the ply cut through with 7 passes at 12mm/sec or 4 passes at 8mm/sec. With the 1.5mm ply, it cut through after 6 passes at 4mm/sec or 4 passes at 2mm/sec. I've gone back onto the original lens primarily since it can give me a smaller kerf than the G7 lens. I've also been getting variable results with the G7 (the second one I got - the first didn't seem any improvement on the original Emblaser supplied lens.) Jim.

Bill, I got some laserable 0.8mm and 1.5mm ply last week from Kitronic https://www.kitronik.co.uk/materials/laser-plywood.html But I have succumbed to the flu bug and I'm just about becoming human again. :-) So I'll try and get a test or two done over the next day or two to see if their stuff is truly laserable. Jim.

I use a piece of 6mm plate glass - part of an old glass shelf from a shop. I hold it in an MDF frame on the base of the machine so that there are a few millimetres of space between the underside of the glass and the alloy base plate. To hold down material I use double sided tape on the glass, but I only use small squares of it positioned outside the cutting area if possible. If you use a large area of double sided tape, removing the cut material from the plate can be very difficult and damage can be caused. Jim.

What did you expect the Tesco staff to do on both occasions? Remeber that a minute fraction of the population of the UK know that your sister is innocent and that the rest of us don't, including staff at Tesco. Jim.

The first question that might be asked is when did Tesco's IT department realise that there was a problem with the card reader software - maybe after several managers had contacted them after having difficult encounters on the shop floor. So if a manager didn't know about the software problems, what did he/she do when a checkout flagged up a stolen card being used? The action taken was correct although the card holder didn't like it. And surely the card readers are there for our convenience as well, otherwise we would have to be carrying around loads of cash since cheques are not accepted by a lot of places these days. Jim.

Is there a proven fact in these two sentences? Jim.

Tesco customer services staff are not paid at the minimum wage level. My grandson worked part time in the local, large Tesco Express for two years on customer services and he was not apathetic or unmotivated - his fellow staff likewise. My own experience of the staff in that Tesco branch does not lead me to believe that they exhibit any tendencies to hate customers. So perhaps you can appraise me of your research which supports your sweeping statement about all customer facing staff in Tesco. It's easy to demean people in jobs which you might consider to be inferior to your own. But someone has to do them or we would all be up the creek. Jim. PS I might ask my grandson for some of his experiences with some customers.

The exact scale relationship for 1:32 scale is that 1/32" equals one inch or 3/8" (12/32) equals one foot. The scale is one of the imperial architectural/engineering scales which equated fractions of an inch to one full scale inch. the next one up in the series is 3/4" scale or 1:16 scale which has 1/16" equal to one prototype inch (3 1/2" gauge) and the next one down in S scale which is 1:64 scale or 1/64" equal to one prototype inch. For metric equivalents, Keith has given all the conversion factors above. The other range of imperial scales was based on duodecimal subdivisions of a foot, for example 1/4" scale or 1:48 (American 0) where 1/48" is equivalent to a prototype inch. In days gone by, it was quite common to get rulers with 1/12" scales and 1/24" and 1/48" subdivisions to work with these scales. Jim.

Giles, I know the feeling. :-) When I started milling metal with small diameter carbide cutters (0.5mm, 1mm) the attrition rate was high, and expensive. :-) But I eventually worked out feeds and speeds which gave a reasonable cutter life. The 7000 rpm top speed of my spindle is technically too slow for small diameter cutters so I finished up working in a grey area outwith manufacturers' recommendations. But you are now enjoying the benefits of CNC - producing parts to an accuracy which could be impossible by hand and all at the press of a button. :-) And a CNC machine is a great help in fending off the ravages of Shakespeare's seventh age of man. :-) Jim.

Peter, The drawing facilities in Cut2D laser are not too bad but nowhere near as comprehensive as what you get in a full blown CAD program like Draftsight. I have Cut2D Desktop for my CNC milling machine and that has recently been upgraded to V9 with improved drafting facilities, but still not quite up to full blown CAD programs. It's possible that Vectric might update Cut2D Laser as well with these facilities. It's a pity you have had problems with Draftsight. I've been using it for a few years and I think I remember having the occasional problem with re-registration but getting round it by re-installing. I just refreshed my memory by Googling your problems and it looks as though they have changed something - probably falling foul of some internet protection setups. But it could be worth keeping trying. AS for the Draftsight interface, it is a copy of the AutoCAD LT interface, and that interface started in pre-Windows days. When AutoDesk had to move to the Windows interface it kept a lot of its original interface to maintain similar working conditions for its users. If you actually get more experience with that interface you would find it faster to use than the normal Windows interface of dialogue boxes. As for your problem with drawing a bunch of lines, one quick way in Draftsight would be to start with one line and use the ARRAY finction to draw however many lines in parallel to the first line at a specified distance apart. I can think of two or three other ways of doing it. :-) Jim.

I have used a small extractor fan which I got in Screwfix for under £20. My Emblaser is in a very large Really Useful box and the fan is fitted in the lid and feeds into a length of flexible tube - also from Screwfix - which leads to an plate fitted into the toplight in my bedroom window. It works very well and might be a bit too powerful for the job. But it is very quiet. Jim.

Hawk, We have lost wax brass loco wheel centres in the S Scale Parts department to be used in wheel making much as you are describing.. The comment I had from the person who originally commissioned the castings was that our supplier's castings don't provide the best detail available but the brass he uses was found to be the best for machining. So it sounds as though there are a few types of casting brass in use, some of which probably don't machine well. Jim.

Alan, I have purchased the Maple Street 1mm, 1.5mm and 2mm MDF and have cut all of these sizes with no apparent problems. I used the 1mm to produce wagon bodies for some kits for the S Scale Society and I must have cut about twenty sets of parts with no problems. I've used the 2mm MDF to cut wagon body parts for 1:32 scale, and again no problems. I haven't had need to work in thicker sizes so I haven't tried their 3mm thick sheet. Noting what Giles has said, Maple Street don't specify their MDF as laser grade and it could be that they source their materials from various sources. Also, I also remember reading somewhere that the very thin MDF sheets are produced by reducing the thickness of thicker sheets by planing or abrading. It could be that the matt finish of the thinner sheets is fine for laser work, but the 3mm sheet may be as produced in the MDF manufacturing process and the shiny surface is acting as a barrier to the laser beam. I do remember working with MDF making desks some years ago and remember the hard shiny finish on the material. I was surprised to note that the very thin sheets had a matt surface - not what I was expecting. I wonder if it is worth doing a test and sanding the surface of a bit of the 3mm to see if the laser cuts with a matt surface.- just for interest's sake. :-) An alternative source of laser suitable 3mm would be the obvious option. Jim.

Alan, I've been cutting a fair bit of that sheet lately with no problems - the low relief factory building further up the thread used that thickness of sheet. I cut at 90%, 16mm/sec(960mm/min) and six passes, so proportionally probably the same cutting power as you. I'm just about to have another session on the same thickness so I'll keep an eye out for any problems. Jim.