Alan_c
Tue 13 October 2009, 15:52
Now for some return on the investment...:)
Challenge for the week (actually it will take about a month at 8 hours per day). Machine a steak board from material supplied; outside cut to shape and a 3D ramp with groove to catch the juices without costing too much?
6700
Finished steakboard before oiling (the client is doing the round over and sanding)
The original sample as supplied had a ramp machined with a ball nose cutter. the ramp runs along the length of the board from the surface down to a depth of about 10mm with a 30mm border around the edge of the board. Initial estimates of the cost to machine 900 of these was quite high as the 3D machining would be a slooow process, so I had to come up with another solution.
I decided to do the job in two stages, stage one would be the outside and groove at the end (actually the groove first of course) and stage two would be the ramp.
6697
Left: Blank in position on Jig1, Centre: Slot and outside cut, Right: ramp cutting jig
To machine stage one required a fairly simple jig that held the board at the bottom edge and at the two corners that would be cut off. A vacuum would have been easier, but I don't have a sufficiently powerful pump. There are three cuts, #1 for the groove in two passes, #2 for the right side of the board from the bottom edge up to the handle and #3 for the left edge up to the handle both in two passes with an 8mm tungsten slot drill - speed 2000mm/min. Doing it this way in seperate paths prevents the corners breaking out as the grain changes direction. its a little slower but with a better end result. The hold down clamps are 20 x 5 mild steel flat held down by furniture screws attached to rumper nuts fixed in the jig from below. Cycle time about 4 min (I could shorten that if I make a better clamp system that locks down faster but there is a height restriction because of my dust foot)
To cut the ramp required a slightly more complicated jig. I decided to hold the work at an angle and just do a straight pocket cut in the area required. The ramp angles were calculated by doing a drawing in CAD of the section and then cut on the machine. Slots were also cut in the jig base for location purposes. There are two ramp supports and one edge locating fence. At the end of the ramps are hold down fingers as part of the jig and two toggle clamps with modified feet to hold the bottom edge down. Cycle time is also about 4 min but most of that is actual cutting as the toggle clamps make for very fast change overs. This is cut with a 12mm slot drill also at 2000m/min.
6698
Ramp angle jig with edge locating fence in the background
6699
Hold down fingers at the bottom of the ramps
6701
Cutting the ramp with a pocket cut (this one is just trimming a mistake in depth setting, it is usually cut in one pass to full depth of 10mm)
The machine is running from 08:00 to 16:45 everyday with breaks at tea time and lunch time. What a pleasure to watch it racking up the Rands at every pass.
The Bosch router that I was a little concerned about at the start regarding heat is cool to the touch at the end of the day (hardly above ambient). The cooling fan produces an extremely strong blast of air that obviously aids in cooling. A cool tool means longer bearing life - I like it;).
When cutting the ramp the X motors get quite hot to the touch, (not too painfull to hold but still within reason) the other two are only just slightly warm.
The dust extraction system is working very nicely, it does not put any strain on the Y car that I can see and follows the machine around like an obedient dog. I had to take it apart at the main pivot to remove a plug of wood slivers and fluffy offcuts this afternoon so I think I may have to change that elbow for one with a clean out panel. This is the first time it has happened but I think it is because of the pocket cutting of the ramp, it produces quite long wooly bits that get sucked up by the foot.
Challenge for the week (actually it will take about a month at 8 hours per day). Machine a steak board from material supplied; outside cut to shape and a 3D ramp with groove to catch the juices without costing too much?
6700
Finished steakboard before oiling (the client is doing the round over and sanding)
The original sample as supplied had a ramp machined with a ball nose cutter. the ramp runs along the length of the board from the surface down to a depth of about 10mm with a 30mm border around the edge of the board. Initial estimates of the cost to machine 900 of these was quite high as the 3D machining would be a slooow process, so I had to come up with another solution.
I decided to do the job in two stages, stage one would be the outside and groove at the end (actually the groove first of course) and stage two would be the ramp.
6697
Left: Blank in position on Jig1, Centre: Slot and outside cut, Right: ramp cutting jig
To machine stage one required a fairly simple jig that held the board at the bottom edge and at the two corners that would be cut off. A vacuum would have been easier, but I don't have a sufficiently powerful pump. There are three cuts, #1 for the groove in two passes, #2 for the right side of the board from the bottom edge up to the handle and #3 for the left edge up to the handle both in two passes with an 8mm tungsten slot drill - speed 2000mm/min. Doing it this way in seperate paths prevents the corners breaking out as the grain changes direction. its a little slower but with a better end result. The hold down clamps are 20 x 5 mild steel flat held down by furniture screws attached to rumper nuts fixed in the jig from below. Cycle time about 4 min (I could shorten that if I make a better clamp system that locks down faster but there is a height restriction because of my dust foot)
To cut the ramp required a slightly more complicated jig. I decided to hold the work at an angle and just do a straight pocket cut in the area required. The ramp angles were calculated by doing a drawing in CAD of the section and then cut on the machine. Slots were also cut in the jig base for location purposes. There are two ramp supports and one edge locating fence. At the end of the ramps are hold down fingers as part of the jig and two toggle clamps with modified feet to hold the bottom edge down. Cycle time is also about 4 min but most of that is actual cutting as the toggle clamps make for very fast change overs. This is cut with a 12mm slot drill also at 2000m/min.
6698
Ramp angle jig with edge locating fence in the background
6699
Hold down fingers at the bottom of the ramps
6701
Cutting the ramp with a pocket cut (this one is just trimming a mistake in depth setting, it is usually cut in one pass to full depth of 10mm)
The machine is running from 08:00 to 16:45 everyday with breaks at tea time and lunch time. What a pleasure to watch it racking up the Rands at every pass.
The Bosch router that I was a little concerned about at the start regarding heat is cool to the touch at the end of the day (hardly above ambient). The cooling fan produces an extremely strong blast of air that obviously aids in cooling. A cool tool means longer bearing life - I like it;).
When cutting the ramp the X motors get quite hot to the touch, (not too painfull to hold but still within reason) the other two are only just slightly warm.
The dust extraction system is working very nicely, it does not put any strain on the Y car that I can see and follows the machine around like an obedient dog. I had to take it apart at the main pivot to remove a plug of wood slivers and fluffy offcuts this afternoon so I think I may have to change that elbow for one with a clean out panel. This is the first time it has happened but I think it is because of the pocket cutting of the ramp, it produces quite long wooly bits that get sucked up by the foot.