What's with the seams on the tops of new cars?
October 11th, 2016, 06:03 PM
#2
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Manufacturing. Unibody cars are mostly sedans, not hardtops anymore. The sidemember panel is the quarter panel, door openings, and the A, B, C, and sometimes D pillars. These are all connected by a curved top piece that ends just inside of the rood edge, and a flat roof is welded on there, and those strips cover the joints. It saves a lot of welding, brazing the sail panels, and I think it's stronger.
Personally, I like the roof rails the older cars have better because it keeps rain from dripping in and it's a place to hang your fingers while cruising.
Personally, I like the roof rails the older cars have better because it keeps rain from dripping in and it's a place to hang your fingers while cruising.
October 12th, 2016, 07:20 AM
#5
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Manufacturing. Unibody cars are mostly sedans, not hardtops anymore. The sidemember panel is the quarter panel, door openings, and the A, B, C, and sometimes D pillars. These are all connected by a curved top piece that ends just inside of the rood edge, and a flat roof is welded on there, and those strips cover the joints. It saves a lot of welding, brazing the sail panels, and I think it's stronger.
.... Tedd
October 12th, 2016, 08:31 AM
#7
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Actually, the real reason is to control production tolerances. The entire side of the car, including the critical door opening, is stamped in one piece (unlike older cars where the door post, roof, quarter panel, and rocker were all separate pieces). This ensures tight tolerances on the door opening and allows for better door fitment and tighter body gaps without needing a lot of time consuming adjustment. The door hinges on these cars are pretty much all welded in place - no adjustment is needed or provided. This construction technique is cheaper, faster to assemble, and produces a car with much higher quality doors and weather sealing.
In case anyone cares, there's still some adjustment in the hinges. My company hangs them at the end of weld shop, paints the cars with them on, and then we take them off in assembly and build them, then put them back on, but I THINK all the adjustment is on the car side of the hinge, and those stay with the car, whereas we remove the door side bolts in assembly.
October 12th, 2016, 10:46 AM
#8
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In case anyone cares, there's still some adjustment in the hinges. My company hangs them at the end of weld shop, paints the cars with them on, and then we take them off in assembly and build them, then put them back on, but I THINK all the adjustment is on the car side of the hinge, and those stay with the car, whereas we remove the door side bolts in assembly.
October 12th, 2016, 07:58 PM
#10
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But the taillights are to big and extravagant.
Railguy
October 13th, 2016, 06:53 AM
#12
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GM used all-welded hinges on it's low-end cars (Nova, Vega, etc) for years. Quality control and panel fit was far less important on those cars; lowest production cost was paramount. These cars still used the separate roof/quarter/rocker/cowl construction, so panel gaps could become massive with welded hinges. GM frankly didn't care at that time. Today's one-piece side construction minimizes tolerances while maintaining lowest production cost.
October 13th, 2016, 06:57 AM
#13
Unisides are actually multiple pieces on some cars. They are laser welded. And it sucks to install them because they come e coated and you can't tell where it's hss or mild steel . You find out when you go to weld em in and you hit a section of steel that does not weld the same as the last usually high strength and mild combo steel. I think dodge is one of them and possibly nissan. Last dodge I did was a combo uniside.
October 13th, 2016, 07:33 AM
#14
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I aways thought and this is only my thoughts. The x body was the model t of its time. It was designed with manufacturing time and ease top priority . Thats why the half frame. Uni body was far superior but more labor intense putting the engine and trans.in a frame along with alot of other components then attaching to back half was much easier . You're right they were low end cars but very reliable .if you need a car but couldn't a ford one that's what you bought. I owned a used vega . I still have it and have to dis agree with them being even close to the same category.
Railguy
Railguy
October 13th, 2016, 08:22 PM
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It's just as easy sticking a powertrain in a unibody as it is a body on frame vehicle, in fact, it's easier, because you can build up the sub frames on separate lines.
In case anyone cares about production engineering, the Indiana plant where I am assigned most of the time used to have body on frame vehicles in both lines, and the suspension lines (which took the frame of the body on frame vehicle) had to hold the front frame and the rear frame of the unibody in the same orientation that was on the same line. Even though both shops no longer have BOF cars on either main line, one shop is still set up that way, and it's a real waste of walking having the guys walk back and forth from the engine to the rear end on each set. We normally have them on separate lines, so the first time the rear end sees the transmission and engine is when they get stuffed into a car from underneath.
In case anyone cares about production engineering, the Indiana plant where I am assigned most of the time used to have body on frame vehicles in both lines, and the suspension lines (which took the frame of the body on frame vehicle) had to hold the front frame and the rear frame of the unibody in the same orientation that was on the same line. Even though both shops no longer have BOF cars on either main line, one shop is still set up that way, and it's a real waste of walking having the guys walk back and forth from the engine to the rear end on each set. We normally have them on separate lines, so the first time the rear end sees the transmission and engine is when they get stuffed into a car from underneath.
October 14th, 2016, 05:54 AM
#16
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copper..you need a resistance spot welder, if you guys are migging sides on you are loosing out..you really dont know til you start using one..especially with the new technology coming out, prices are reasonable..you will make more money day to day with a spot welder than any other piece of metal equip in the shop..not talking as a salesman...ive been using them for a decade, i dont know how i made any money when i was young and working oin the line migging, grinding, filling, painting etc...
if i worked in a shop with out one..id buy my own or quit..thats how much i believe in them
John, are you at the GM truck plant? My company sold them spot welders to assemble the tail gates...talk about a big place..
i think they go thru welders about every 2 years, ive been gone from that zone for a long time, but i loved living in Indiana..i miss it..i dont know what they are doing in there now, but last time i talked to the rep that replaced me they where still using them
if i worked in a shop with out one..id buy my own or quit..thats how much i believe in them
John, are you at the GM truck plant? My company sold them spot welders to assemble the tail gates...talk about a big place..
i think they go thru welders about every 2 years, ive been gone from that zone for a long time, but i loved living in Indiana..i miss it..i dont know what they are doing in there now, but last time i talked to the rep that replaced me they where still using them
October 14th, 2016, 07:09 AM
#17
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It's just as easy sticking a powertrain in a unibody as it is a body on frame vehicle, in fact, it's easier, because you can build up the sub frames on separate lines.
In case anyone cares about production engineering, the Indiana plant where I am assigned most of the time used to have body on frame vehicles in both lines, and the suspension lines (which took the frame of the body on frame vehicle) had to hold the front frame and the rear frame of the unibody in the same orientation that was on the same line. Even though both shops no longer have BOF cars on either main line, one shop is still set up that way, and it's a real waste of walking having the guys walk back and forth from the engine to the rear end on each set. We normally have them on separate lines, so the first time the rear end sees the transmission and engine is when they get stuffed into a car from underneath.
In case anyone cares about production engineering, the Indiana plant where I am assigned most of the time used to have body on frame vehicles in both lines, and the suspension lines (which took the frame of the body on frame vehicle) had to hold the front frame and the rear frame of the unibody in the same orientation that was on the same line. Even though both shops no longer have BOF cars on either main line, one shop is still set up that way, and it's a real waste of walking having the guys walk back and forth from the engine to the rear end on each set. We normally have them on separate lines, so the first time the rear end sees the transmission and engine is when they get stuffed into a car from underneath.
Well I did say its just what I thought.
What do mean by build up the sub frame on a separate line? And I'm talking mid 60s to mid 70s.
Am I right about the uni body being far superior? If so then why did it take so long before they were used? Just wondering.
Railguy
October 14th, 2016, 08:30 AM
#18
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Unibodies were used on some common American cars prior to the present time.
For instance, I know they were used on the Lincoln Zephyr from 1936 onward, on the Thunderbird from '61 to '63 (and possibly earlier), and possibly on the Cord.
- Eric
For instance, I know they were used on the Lincoln Zephyr from 1936 onward, on the Thunderbird from '61 to '63 (and possibly earlier), and possibly on the Cord.
- Eric
October 14th, 2016, 08:32 AM
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Mark, I'm at the Toyota plant in Princeton.
Rail, the way our plants are laid out is the cars come in the assembly shop from paint, run down the trim lines and get the instrument panel, headliner, and other things, then down chassis, then down final where they get seats and wheels and other things, then out to inspection. Chassis mainly consists of bolting things to the bottom of the unibody like the fuel tank, brake lines, and the front suspension assembly (h frame, engine, transaxle, macpherson struts) and the rear suspension module (rsm frame, rear diff if it has one).
The chassis lines have sub lines. There's an engine line that bolts engine to transaxle, puts the shafts in, and other things. That powertrain goes to a front suspension line where it is landed on an h frame and built up. Meanwhile, there is a separate line to build up the RSMs. This is more efficient because you can standardize the work, and make the assemblies on the line much closer. If you had it in body-on-frame layout, the whole frame would be built up in one piece because it is one chunk. and that's huge, but, more importantly, any unibodies sharing the line would be built up the same way, so it's inefficient.
Rail, the way our plants are laid out is the cars come in the assembly shop from paint, run down the trim lines and get the instrument panel, headliner, and other things, then down chassis, then down final where they get seats and wheels and other things, then out to inspection. Chassis mainly consists of bolting things to the bottom of the unibody like the fuel tank, brake lines, and the front suspension assembly (h frame, engine, transaxle, macpherson struts) and the rear suspension module (rsm frame, rear diff if it has one).
The chassis lines have sub lines. There's an engine line that bolts engine to transaxle, puts the shafts in, and other things. That powertrain goes to a front suspension line where it is landed on an h frame and built up. Meanwhile, there is a separate line to build up the RSMs. This is more efficient because you can standardize the work, and make the assemblies on the line much closer. If you had it in body-on-frame layout, the whole frame would be built up in one piece because it is one chunk. and that's huge, but, more importantly, any unibodies sharing the line would be built up the same way, so it's inefficient.
October 14th, 2016, 09:29 AM
#21
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yes, unibodies are cheaper by today's standard. But I was referring to mid 60s to mid 70s.
railguy
October 14th, 2016, 09:38 AM
#22
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Newer cars often have the rear suspension as a sort of a subframe assembly as well, which bolts up to the body with just a few fasteners.
I may be mistaken, but I believe that for large assemblies like the X-body unibody segments, GM did use automated welders - clamp frame in position, spot welders come out to frame all at once, weld their spots, then retract and on to the next station - sort of a block containing a number of discrete welding units moving together.
I believe what they have now is computer-controlled welding arms that swing around and weld numerous sites each.
- Eric
October 14th, 2016, 11:09 AM
#23
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Rail, yes, you're right, I think we're saying the same thing differently.
Eric, yes, all the welding is robotic except for backup. Robots move the parts, hold the parts, spot weld the parts, and mig weld some as well.
Eric, yes, all the welding is robotic except for backup. Robots move the parts, hold the parts, spot weld the parts, and mig weld some as well.
October 15th, 2016, 06:35 AM
#25
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My 1962 F-85 wagon is unibody (as are all the 1961-63 Y-body cars)
October 15th, 2016, 06:57 AM
#26
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