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FMB Turbo 20-100: Questions & Answers

How do I 'home' the bar feeder (also referred to as 'resetting the zero point')?

FMB Bosch controls: Begin with the guide channel closed and the bar pusher about a foot forward from the rearmost position from the lathe. Press the F7 button on the manual screen to go to the Automatic screen. Press and hold the “UP” arrow (located on the right side of the screen) and push the F1 “REF” button. The bar pusher will move to the rear of the bar feeder until it reaches the home proximity switch which will reset the reference or home position.

How do I shorten my remnant length?

FMB Bosch controls: The remnant length is controlled by the parameters “Front Limit Position” and “Part Length”, the distance from the chuck or guide bushing the cut-off occurs and the length of the material in the guide channel. The front limit position is the farthest the bar pusher can travel forward into the lathe. The part length is the sum of the overall part length, the width of the cut-off tool and the amount of material left for facing. When the pusher doesn’t have enough travel left to move the distance in the part length parameter before reaching the front limit position the End of Bar signal is sent. If the remnant is too long verify the front limit position parameter and the part length parameter.

Keep in mind that on all lathes there will be a certain amount of unusable material. This unusable length can be measured by moving the bar pusher as far as possible into the lathe and and measuring from the cut-off tool to the inside of the bar feeder collet stop. For Swiss type lathes move the headstock to the cut-off position and measure from the back of the cut-off tool to the stop inside the bar feeder collet. This measurement is your minimum remnant length. The remnant length can be up to one part length longer than the minimum depending on home much material is remaining.

How do I set my 'end-of-bar' (FMB: 'front limit position')?

FMB Bosch controls: Before beginning reference (re-zero) the bar pusher. For sliding headstock machines only, move the headstock into overtravel toward the guide bushing. For all machines, move the bar pusher with a collet attached, no material in the channel, forward until the bar pusher collet contacts the lathe collet. Smaller diameter bar pushers may travel inside the lathe collet, larger diameter bar pushers may stop sooner at the back of the collet or at the collet sleeve. Record the position of the bar pusher from the main screen and enter the position minus 3mm (1/8 inch) in the service parameters, position page under the Front Limit Position parameter. To get to the front limit position parameter, press the F7 “SERV” button from the Manual screen. The service menu will be displayed. Press the down arrow to open the positions parameters. A list of position parameters will show on the screen. Press the Edit button (located to the left of the Print button) to open the parameters for editing. A parameter will be highlighted. If the highlighted parameter is not the one to be changed use the up or down arrow buttons to move to the desired parameter. Highlight the Front Limit Position parameter. Type the new value and press the Edit key to enter the value and lock the parameters. Please note that if the guide channel size is changed the bar pusher of the new channel may have a different stopping point in the spindle than the bar pusher originally used to set up the machine. In this case the parameter should be altered to reflect the change in the maximum forward travel of the bar pusher.

How do I set the 'top cut' position (first insert position / facing length)?

FMB Bosch controls: The first insert position controls where the new bar stops in the lathe during a bar change. The value of the parameter is a measurement of the distance from the facing flag to the face of the guide bushing (minus 2 inches, Swiss type lathes only) or to the face of the chuck/collet (Fixed headstock lathes). The position can be extended further into the lathe with the Extension of First Insert parameter in the Part Special Settings menu. The easiest way to set the parameter is to take a measurement with a steel tape measure. Press the F11 SERV button on the manual screen, then press the down arrow for the Positions menu. Press the Edit key (located to the left of the Print button) to unlock the parameter for editing. If the highlighted parameter is not the one needed use the up or down arrow to move to the correct parameter. Type the dimension and press the Edit key to store the change and lock the parameter. To move the bar further into the lathe use the Extension of First Insert parameter. Press the F10 Part button, then press the right arrow button for the Special menu. Press the Edit button and use the down arrow to move the cursor to the Extension of First Insert parameter. Type the desired value, press enter and press the Edit button to store the change and lock the parameter.

How do I prevent the pusher-collet assembly from disengaging with bar stock in a sliding headstock (Swiss) lathe?

FMB Bosch controls: The most common cause for losing the bar from the pusher collet is the lack of a dwell or too small a dwell in the part program after the lathe collet opens and after the lathe collet closes. The dwell is required to allow time for the signal from the lathe to reach the bar feeder and for the bar feeder to act on the signal. Another cause for losing the material from the bar feeder collet is jogging the headstock when the synchronization is not engaged. The sync will only engage if the bar feeder is in Automatic, Step 17 is on and the lathe collet is closed. Moving the headstock with the collet closed but without the other conditions met can cause the bar stock to pull out of the feeder collet. Looseness in the linkage of the sync device, a worn rotating tip, obstructions to the bar pusher in the channel or nose and slack in the synchronization or drive belt can also contribute to losing the stock from the pusher collet.

What parameters or settings do I have to change when setting up a new job?

FMB Bosch controls: When changing to a new job the part length parameter in the PART menu, Standard Settings should be changed. The proper setting is the sum of the overall part length + the width of the cut-off tool + any facing stock used. This dimension reflects the total amount of material required to make and cut off one part. The first insert length may need to be altered in case of a left handed cutoff tool or to provide a longer “stick-out” of material on the bar reload. This can be accomplished through the parameter “Extension of First Insert”, located in the PART menu under the Special Settings section. This parameter will allow the new bar to travel farther into the lathe at bar change by the distance of the entered value. The speed and force for part follow-up parameters normally are not changed but can be in special cases such as extremely small or large diameters or flexible material. These parameters can be found in the PART menu under the Standard Settings section.

Explain the dwells I need to have present in my lathe program to accommodate the bar feeder?

FMB Bosch controls: We recommend a ½ second dwell in the main part program after the collet opens and after the collet closes for Swiss type lathe applications to allow the signal for the lathe collet open to reach the bar feeder and be processed. This allows the synchronization device time to release at the collet open signal and to reengage at the closed collet signal. For fixed headstock lathes a dwell is required in the part program to give the bar feeder time to advance the material for the next part before the collet closes. The length of dwell is dependent on the length of the part to be feed out.

How do you set the chain/belt tension on my bar feeder?

FMB Bosch controls: The drive belt tension is adjusted by moving the bearing blocks for the driven pulley shaft rearward. To check the belt tension move the pusher all the way to the rear so the S1 proximity switch is lighted. Use a small allen wrench or small bar with a 90 degree bend to lift the drive belt in the area near the gripper assembly. The belt should lift about 19mm, (3/4″) with light resistance. With heavy resistance the belt should come nearly to the guard plate. To make an adjustment to the drive belt tension remove the metal box that covers the motor pulley and belt to the driven shaft pulley. This is located inside the sheet metal near the S1 proximity switch. Remove the rear plate of the bar feeder. It may also be necessary to remove the large sheet metal cover on the back side of the bar feeder if you cannot reach all the bolts on the back side bearing block. The cover is in two sections, remove only the rear section to gain access to the far side bearing block. Loosen the four bolts in each bearing block. Use the jack screws next to each bearing block to move the blocks to the rear (away from the lathe) until the proper tension is reached. Be sure to move both sides equal amounts to maintain proper tracking of the drive belt on the pulley. Tighten the screws in the bearing blocks and move the bar pusher forward and backward to check for smooth operation and belt tracking. If the belt rides against one side of the pulley move the bearing block on the opposite side to the rear to straighten out the tracking. When finished, re-zero the bar pusher.

How do I adjust the steady rest rollers for different stock diameters?

FMB Bosch controls: Open the steady rest on the Manual screen. Load a bar into the lathe and close the lathe collet. Close the steady rest from the Manual screen. Turn the rear adjusting screw (the taller of the two adjusting screws, the one furthest from the steady rest door) counter clockwise until the screw rotates freely and the rollers are resting against the bar stock. Turn the rear screw clockwise until resistance is felt. Open the steady rest from the Manual screen. Turn the rear screw clockwise an additional two turns. Close the steady rest and check to make sure there is enough clearance between the bar stock and the rollers that the rollers can spin. The rollers may not all be able to spin due to the stock sagging but there should be sufficient clearance that the bar can move within the rollers. The front adjusting screw (the shorter of the two adjusting screws, closest to the steady rest door) can be used to limit the opening of the rollers so they will just clear the bar pusher in case extra support is needed after the roller opening.

How do I determine which bushing block (bearing block) to use in my steady rest for a specific bar stock diameter?

FMB Bosch controls: The bushing blocks have an approximate range of two millimeters with a clearance of one millimeter. For example, the 10mm bushing block has a stock size range of 7mm to 9mm and the 22mm bushing block has a size range of 19mm to 21mm. The blocks are sold individually, it takes 2 blocks to make a set.